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Elena Uribe - One of the best experts on this subject based on the ideXlab platform.
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Cloning of two LIMCH1 isoforms: characterization of their distribution in rat brain and their Agmatinase activity
Histochemistry and Cell Biology, 2016Co-Authors: David García, Nelson Carvajal, José Benítez, Arlette González, Vasthi López, Patricio Ordenes, María A. García-robles, Elena UribeAbstract:Agmatine, a precursor for polyamine biosynthesis, is also associated with neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. This molecule results from the decarboxylation of l -arginine by arginine decarboxylase, and it is hydrolyzed to urea and putrescine by Agmatinase. Recently, we have described a new protein that also hydrolyzes agmatine, Agmatinase-like protein (ALP), which was identified through immunohistochemical analysis in the hypothalamus and hippocampus of rats. However, its sequence differs greatly from all known Agmatinases and does not contain the typical Mn^2+ ligands associated with the urea hydrolase family of proteins. ALP has a LIM-like domain close to its carboxyl terminus, and the removal of which results in a truncated variant with a tenfold increased k _cat value and a threefold decreased K _ m value for agmatine. Analysis of the gene database revealed several transcripts, denominated LIMCH1 isoforms, with extreme 3′ sequences identical to ALP. Limch1 gene products have been described as members of a multi-domain family of proteins with the biggest isoform containing a calponin homology (CH) domain at its N-terminus. Here, we cloned two LIMCH1 transcripts, one of 3177 bp and the other of 2709 bp (ALP contains 1569 bp) and analyzed LIMCH1 expression and distribution in rat brain using RT-PCR, Western blot and immunohistochemical analyses. LIMCH1 was detected mainly in the hypothalamic and hippocampal regions, which is similar to the distribution of ALP and agmatine in brain. In addition, we cloned and expressed both isoforms in E. coli and confirmed that they were catalytically active on agmatine with kinetic parameters similar to ALP. LIM domain-truncated variants of both isoforms moderately increased the k _cat and catalytic efficiency. Thus, we propose that LIMCH1 is useful to regulate the intracellular concentrations of the neurotransmitter/neuromodulator, agmatine.
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further insight into the inhibitory action of a lim double zinc finger motif of an Agmatinase like protein
Journal of Inorganic Biochemistry, 2014Co-Authors: Jaime Cofré, Nelson Carvajal, José Benítez, David García, Alejandro Vallejos, Paola Montes, Jose Martinezoyanedel, Elena UribeAbstract:Abstract Agmatine is a precursor for polyamine biosynthesis also associated to neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. It results from decarboxylation of l -arginine by arginine decarboxylase and it is hydrolyzed to urea and putrescine by Agmatinase. Recently, we have described a new protein which also hydrolyzes agmatine although its sequence greatly differs from all known Agmatinases. This Agmatinase-like protein (ALP) contains a LIM-like double Zn-finger domain close to its carboxyl terminus, whose removal results in a truncated variant with a 10-fold increased k cat , and a 3-fold decreased K m value for agmatine. Our proposal was that the LIM-domain functions as an autoinhibitory, regulatory entity for ALP. Results in this report provide additional support for the postulated inhibitory effect. The purified isolated LIM domain was shown to be competitively inhibitory to a truncated variant ALP (lacking the LIM-domain), but not to the wild-type species. The C453A variant was shown to be a Zn 2 + -free enzyme with kinetic parameters similar to those of the truncated-ALP. A molecular dynamic simulation of a modeled LIM-domain 3D structure showed that, as a consequence of C453A mutation, the coordination of the zinc ion is broken and the structure of the zinc finger is melted. The inhibitory action of the LIM/double Zinc-finger motif was associated to a significant conformational change, as detected by tryptophan fluorescence studies, but was not related to changes in the association of the enzyme with the catalytically essential Mn 2 + .
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Further insight into the inhibitory action of a LIM/double zinc-finger motif of an Agmatinase-like protein.
Journal of inorganic biochemistry, 2013Co-Authors: Jaime Cofré, Nelson Carvajal, José Benítez, David García, Alejandro Vallejos, Paola Montes, José Martínez-oyanedel, Elena UribeAbstract:Abstract Agmatine is a precursor for polyamine biosynthesis also associated to neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. It results from decarboxylation of l -arginine by arginine decarboxylase and it is hydrolyzed to urea and putrescine by Agmatinase. Recently, we have described a new protein which also hydrolyzes agmatine although its sequence greatly differs from all known Agmatinases. This Agmatinase-like protein (ALP) contains a LIM-like double Zn-finger domain close to its carboxyl terminus, whose removal results in a truncated variant with a 10-fold increased k cat , and a 3-fold decreased K m value for agmatine. Our proposal was that the LIM-domain functions as an autoinhibitory, regulatory entity for ALP. Results in this report provide additional support for the postulated inhibitory effect. The purified isolated LIM domain was shown to be competitively inhibitory to a truncated variant ALP (lacking the LIM-domain), but not to the wild-type species. The C453A variant was shown to be a Zn 2 + -free enzyme with kinetic parameters similar to those of the truncated-ALP. A molecular dynamic simulation of a modeled LIM-domain 3D structure showed that, as a consequence of C453A mutation, the coordination of the zinc ion is broken and the structure of the zinc finger is melted. The inhibitory action of the LIM/double Zinc-finger motif was associated to a significant conformational change, as detected by tryptophan fluorescence studies, but was not related to changes in the association of the enzyme with the catalytically essential Mn 2 + .
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Evidence for an inhibitory LIM domain in a rat brain Agmatinase-like protein.
Archives of biochemistry and biophysics, 2011Co-Authors: Víctor Castro, Nelson Carvajal, José Benítez, Pablo Fuentealba, Adolfo Henríquez, Alejandro Vallejos, Marcela Lobos, Beatriz Díaz, Elena UribeAbstract:Abstract We recently cloned a rat brain Agmatinase-like protein (ALP) whose amino acid sequence greatly differs from other Agmatinases and exhibits a LIM-like domain close to its carboxyl terminus. The protein was immunohistochemically detected in the hypothalamic region and hippocampal astrocytes and neurons. We now show that truncated species, lacking the LIM-type domain, retains the dimeric structure of the wild-type protein but exhibits a 10-fold increased k cat , a 3-fold decreased K m value for agmatine and altered intrinsic tryptophan fluorescent properties. As expected for a LIM protein, zinc was detected only in the wild-type ALP (∼2 Zn 2+ /monomer). Our proposal is that the LIM domain functions as an autoinhibitory entity and that inhibition is reversed by interaction of the domain with some yet undefined brain protein.
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Expression and localization of an Agmatinase-like protein in the rat brain
Histochemistry and Cell Biology, 2010Co-Authors: Claudia Mella, Nelson Carvajal, Fernando Martínez, María Angeles García, Francisco Nualart, Víctor Castro, Paulina Bustos, Elena UribeAbstract:Agmatinase catalyzes the hydrolysis of agmatine into putrescine and urea, and agmatine (decarboxylated l -arginine) plays several roles in mammalian tissues, including neurotransmitter/neuromodulatory actions in the brain. Injection of agmatine in animals produces anticonvulsant, antineurotoxic and antidepressant-like actions. Information regarding the enzymatic aspects of agmatine metabolism in mammals, especially related to its degradation, is relatively scarce. The explanation for this is the lack of enzymatically active preparations of mammalian Agmatinase. Recently, we have cloned a protein from a cDNA rat brain library having Agmatinase activity although its amino acid sequence greatly differs from all known Agmatinases, we called Agmatinase-like protein. In this work, we analyzed the expression of this enzyme in the rat brain by means of RT-PCR and immunohistochemical analysis using a polyclonal antibody generated against the recombinant Agmatinase-like protein. The Agmatinase-like protein was detected in the hypothalamus in glial cells and arcuate nucleus neurons, and in hippocampus astrocytes and neurons, but not in brain cortex. In general, detected localization of Agmatinase-like protein coincides with that described for its substrate agmatine and our results help to explain several reported effects of agmatine in the brain. Concretely, a role in the regulation of intracellular concentrations of the neurotransmitter/neuromodulator agmatine is suggested for the brain Agmatinase-like protein.
Nelson Carvajal - One of the best experts on this subject based on the ideXlab platform.
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Mammalian Agmatinases constitute unusual members in the family of Mn2+-dependent ureahydrolases.
Journal of inorganic biochemistry, 2016Co-Authors: Nicol Romero, José Benítez, David García, Arlette González, Vasthi López, Gerhard Schenk, María De Los Ángeles García-robles, Leonardo Bennun, Liam A. Wilson, Nelson CarvajalAbstract:Agmatine (1-amino-4-guanidinobutane) plays an important role in a range of metabolic functions, in particular in the brain. Agmatinases (AGMs) are enzymes capable of converting agmatine to the polyamine putrescine and urea. AGMs belong to the family of Mn-dependent ureahydrolases. However, no AGM from a mammalian source has yet been extracted in catalytically active form. While in human AGM the six amino acid ligands that coordinate the two Mn ions in the active site are conserved, four mutations are observed in the murine enzyme. Here, we demonstrate that similar to its human counterpart murine AGM does not appear to have in vitro catalytic activity, independent of the presence of Mn. However, in presence of agmatine both enzymes are very efficient in promoting cell growth of a yeast strain that is deficient in polyamine biosynthesis (Saccharomyces cerevisiae strain TRY104Δspe1). Furthermore, mutations among the putative Mn binding residues had no effect on the ability of murine AGM to promote growth of the yeast culture. It thus appears that mammalian AGMs form a distinct group within the family of ureahydrolases that (i) either fold in a manner distinct from other members in this family, or (ii) require accessory proteins to bind Mn in a mechanism related to that observed for the Ni-dependent urease.
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Cloning of two LIMCH1 isoforms: characterization of their distribution in rat brain and their Agmatinase activity
Histochemistry and Cell Biology, 2016Co-Authors: David García, Nelson Carvajal, José Benítez, Arlette González, Vasthi López, Patricio Ordenes, María A. García-robles, Elena UribeAbstract:Agmatine, a precursor for polyamine biosynthesis, is also associated with neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. This molecule results from the decarboxylation of l -arginine by arginine decarboxylase, and it is hydrolyzed to urea and putrescine by Agmatinase. Recently, we have described a new protein that also hydrolyzes agmatine, Agmatinase-like protein (ALP), which was identified through immunohistochemical analysis in the hypothalamus and hippocampus of rats. However, its sequence differs greatly from all known Agmatinases and does not contain the typical Mn^2+ ligands associated with the urea hydrolase family of proteins. ALP has a LIM-like domain close to its carboxyl terminus, and the removal of which results in a truncated variant with a tenfold increased k _cat value and a threefold decreased K _ m value for agmatine. Analysis of the gene database revealed several transcripts, denominated LIMCH1 isoforms, with extreme 3′ sequences identical to ALP. Limch1 gene products have been described as members of a multi-domain family of proteins with the biggest isoform containing a calponin homology (CH) domain at its N-terminus. Here, we cloned two LIMCH1 transcripts, one of 3177 bp and the other of 2709 bp (ALP contains 1569 bp) and analyzed LIMCH1 expression and distribution in rat brain using RT-PCR, Western blot and immunohistochemical analyses. LIMCH1 was detected mainly in the hypothalamic and hippocampal regions, which is similar to the distribution of ALP and agmatine in brain. In addition, we cloned and expressed both isoforms in E. coli and confirmed that they were catalytically active on agmatine with kinetic parameters similar to ALP. LIM domain-truncated variants of both isoforms moderately increased the k _cat and catalytic efficiency. Thus, we propose that LIMCH1 is useful to regulate the intracellular concentrations of the neurotransmitter/neuromodulator, agmatine.
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insight on the interaction of an Agmatinase like protein with mn2 activator ions
Journal of Inorganic Biochemistry, 2015Co-Authors: Matías Quiñones, Nelson Carvajal, Jaime Cofré, José Benítez, David García, Nicol Romero, Arlette González, María De Los Angeles García, Vasthi López, Gerhard SchenkAbstract:Agmatinase is an enzyme that catalyzes the hydrolysis of agmatine, a compound that is associated with numerous functions in the brain of mammalian organisms such as neurotransmitter, anticonvulsant, antinociceptive, anxiolytic and antidepressant-like actions. To date the only characterized Agmatinases with significant enzymatic activity were extracted from bacterial organisms. These Agmatinases are closely related to another ureahydrolase, arginase; both have binuclear Mn2+ centers in their active sites. An Agmatinase-like protein (ALP) from rat brain was identified that bears no sequence homology to known Agmatinases (E. Uribe, M. Salas, S. Enriquez, M.S. Orellana, N. Carvajal, Arch. Biochem. Biophys. 461(2007) 146-150). Since all known ureahydrolases contain histidines in their binuclear Mn2+ site each of the five histidine residues in ALP was individually replaced by alanines to identify those that may be involved in metal ion binding. Reactivation assays and thermal stability measurements indicated that His206 is likely to interact with a Mn2+ bound to a high affinity site. In contrast, His65 and possibly His435 are important for binding of a second Mn2+ to a lower affinity site. Metal ion binding to that site is not only leading to an increase in reactivity but also enzyme stability. Thus, similar to bacterial Agmatinases and some of the antibiotic-degrading, Zn2+-dependent metallo-beta-lactamases ALP appears to be active in the mono and binuclear form, with binding of the second metal ion increasing both reactivity and stability. (C) 2015 Elsevier Inc. All rights reserved.
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Insight on the interaction of an Agmatinase-like protein with Mn2 + activator ions
Journal of inorganic biochemistry, 2015Co-Authors: Matías Quiñones, Nelson Carvajal, Jaime Cofré, José Benítez, David García, Nicol Romero, Arlette González, María De Los Angeles García, Vasthi López, Gerhard SchenkAbstract:Agmatinase is an enzyme that catalyzes the hydrolysis of agmatine, a compound that is associated with numerous functions in the brain of mammalian organisms such as neurotransmitter, anticonvulsant, antinociceptive, anxiolytic and antidepressant-like actions. To date the only characterized Agmatinases with significant enzymatic activity were extracted from bacterial organisms. These Agmatinases are closely related to another ureahydrolase, arginase; both have binuclear Mn2+ centers in their active sites. An Agmatinase-like protein (ALP) from rat brain was identified that bears no sequence homology to known Agmatinases (E. Uribe, M. Salas, S. Enriquez, M.S. Orellana, N. Carvajal, Arch. Biochem. Biophys. 461(2007) 146-150). Since all known ureahydrolases contain histidines in their binuclear Mn2+ site each of the five histidine residues in ALP was individually replaced by alanines to identify those that may be involved in metal ion binding. Reactivation assays and thermal stability measurements indicated that His206 is likely to interact with a Mn2+ bound to a high affinity site. In contrast, His65 and possibly His435 are important for binding of a second Mn2+ to a lower affinity site. Metal ion binding to that site is not only leading to an increase in reactivity but also enzyme stability. Thus, similar to bacterial Agmatinases and some of the antibiotic-degrading, Zn2+-dependent metallo-beta-lactamases ALP appears to be active in the mono and binuclear form, with binding of the second metal ion increasing both reactivity and stability. (C) 2015 Elsevier Inc. All rights reserved.
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further insight into the inhibitory action of a lim double zinc finger motif of an Agmatinase like protein
Journal of Inorganic Biochemistry, 2014Co-Authors: Jaime Cofré, Nelson Carvajal, José Benítez, David García, Alejandro Vallejos, Paola Montes, Jose Martinezoyanedel, Elena UribeAbstract:Abstract Agmatine is a precursor for polyamine biosynthesis also associated to neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. It results from decarboxylation of l -arginine by arginine decarboxylase and it is hydrolyzed to urea and putrescine by Agmatinase. Recently, we have described a new protein which also hydrolyzes agmatine although its sequence greatly differs from all known Agmatinases. This Agmatinase-like protein (ALP) contains a LIM-like double Zn-finger domain close to its carboxyl terminus, whose removal results in a truncated variant with a 10-fold increased k cat , and a 3-fold decreased K m value for agmatine. Our proposal was that the LIM-domain functions as an autoinhibitory, regulatory entity for ALP. Results in this report provide additional support for the postulated inhibitory effect. The purified isolated LIM domain was shown to be competitively inhibitory to a truncated variant ALP (lacking the LIM-domain), but not to the wild-type species. The C453A variant was shown to be a Zn 2 + -free enzyme with kinetic parameters similar to those of the truncated-ALP. A molecular dynamic simulation of a modeled LIM-domain 3D structure showed that, as a consequence of C453A mutation, the coordination of the zinc ion is broken and the structure of the zinc finger is melted. The inhibitory action of the LIM/double Zinc-finger motif was associated to a significant conformational change, as detected by tryptophan fluorescence studies, but was not related to changes in the association of the enzyme with the catalytically essential Mn 2 + .
Fuller W Bazer - One of the best experts on this subject based on the ideXlab platform.
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Effects of catecholamines on secretion of interferon tau and expression of genes for synthesis of polyamines and apoptosis by ovine trophectoderm
Biology of reproduction, 2018Co-Authors: Mohammed A. Elmetwally, Yasser Y. Lenis, Wanjin Tang, Fuller W BazerAbstract:Ovine trophectoderm (oTr1) cells were used to investigate effects of epinephrine (EP), norepinephrine (NE), and dopamine (DA) on their proliferation, migration and adhesion, secretion of interferon tau (IFNT), and expression of genes for synthesis of polyamines and apoptosis. Expression of mRNAs for Agmatinase (AGMAT), arginine decarboxylase (ADC), ornithine decarboxylase (ODC1), and solute carrier family 7 (SLC7A1) (cationic amino acid transporter, Y + system), member 1 increased (P
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Effects of Bisphenol-A on proliferation and expression of genes related to synthesis of polyamines, interferon tau and insulin-like growth factor 2 by ovine trophectoderm cells.
Reproductive toxicology (Elmsford N.Y.), 2018Co-Authors: Mohammed A. Elmetwally, Yasser Y. Lenis, Wanjin Tang, Amal A. Halawa, Fuller W BazerAbstract:Abstract This study evaluated the effects of bisphenol A (BPA) on proliferation of ovine trophectoderm (oTr1) cells, as well as expression of genes for transport of arginine and synthesis of polyamines. BPA reduced proliferation of oTr1 cells at concentrations of 1 × 10−6, 1 × 10−5, 1 × 10−4 M compared to concentrations of 0, 1 × 10−9, and 1 × 10−8 M at 24 and 96 h of culture. Lower concentrations of BPA significantly increased expression of mRNAs for Agmatinase (AGMAT), arginine decarboxylase (ADC), ornithine decarboxylase (ODC1) and solute carrier family 7 member 1 (SLC7A1). Similarly, synthesis of polyamines by oTr1 cells was greatest at lower concentrations of BPA and decreased as the dose of BPA increased. Expression of mRNAs for interferon tau (IFNT) and insulin-like growth factor 2 (IGF2) by oTr1 cells was greater than for controls at 1 × 10−9 M BPA. Overall, the effects of BPA on proliferation and gene expression by oTr1 cells were highly dose-dependent.
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Functional roles of Agmatinase during the peri-implantation period of pregnancy in sheep
Amino Acids, 2018Co-Authors: Yasser Y. Lenis, Mohammed A. Elmetwally, Kathrin Dunlap, Wanjin Tang, Carey Satterfield, Guoyao Wu, Fuller W BazerAbstract:This study investigated the effect of agmatine (Agm) in proliferation of ovine trophecdoderm cells (oTr1) as well as the importance of the arginine decarboxylase (ADC) and Agmatinase (AGMAT) alternative pathway for synthesis of polyamines in ovine conceptuses during the peri-implantation period of pregnancy. Morpholino antisense oligonucleotides (MAOs) were used to inhibit translation of mRNAs for ODC1 alone, AGMAT alone, and their combination. Rambouillet ewes (N = 50) were assigned randomly to the following treatments on Day 8 of pregnancy: MAO control (n = 10); MAO-ODC1 (n = 8); MAO-ADC (n = 6); MAO-ODC1:MAO-ADC (n = 9); or MAO-ODC1:MAO-AGMAT (n = 9). Ewes were ovario-hysterectomized on Day 16 of pregnancy to obtain uterine flushings, uterine endometrium, and conceptus tissues. Inhibition of translation of both ODC1 and AGMAT resulted in 22% of ewes having morphologically and functionally normal (elongated and healthy) conceptuses designated MAO-ODC1:MAO-AGMAT (A). But, 78% of the MAO-ODC1:MAO-AGMAT ewes had morphologically and functionally abnormal (not elongated and fragmented) conceptuses designated MAO-ODC1:MAO-AGMAT (B). The pregnancy rate was less (22%; P
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Biosynthesis of Polyamines for Development of Mammalian Conceptuses1
2016Co-Authors: Alternative Pathway For De Novo, Xiaoqiu Wang, Wei Ying, Kathrin A. Dunlap, Gang Lin, Carey M. Satterfield, Robert C, Fuller W BazerAbstract:Ornithine decarboxylase (ODC1) is considered the rate-controlling enzyme for the classical de novo biosynthesis of polyamines (putrescine, spermidine, and spermine) in mammals. However, metabolism of arginine to agmatine via arginine decarboxylase (ADC) and conversion of agmatine to polyamines via Agmatinase (AGMAT) is an alternative pathway long recognized in lower organisms, but only recently suggested for neurons and liver cells of mammals. We now provide evidence for a functional ADC/AGMAT pathway for the synthesis of polyamines in mammalian reproductive tissue for embryonic survival and development. We first investigated cellular func-tions of polyamines by in vivo knockdown of translation of mRNA for ODC1 in ovine conceptus trophectoderm using morpholino antisense oligonucleotides (MAOs) and found tha
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effects of agmatine on secretion of interferon tau and catecholamines and expression of genes related to production of polyamines by ovine trophectoderm cells
Amino Acids, 2016Co-Authors: Yasser Y. Lenis, Wanjin Tang, Xiaoqiu Wang, Fuller W BazerAbstract:Embryonic survival requires histotrophic nutrition, including molecules secreted or transported into the uterine lumen by uterine epithelia. l-Arginine (Arg) is a common substrate for synthesis of nitric oxide, ornithine, proline, glutamate, creatinine, urea, polyamines and agmatine. Agmatine (Agm) is a product of arginine decarboxylation and it is a substrate for Agmatinase for synthesis of putrescine and other polyamines in the ovine conceptus. Polyamines are essential for conceptus development. Therefore, this study compared effects of Arg and Agm on the behavior of ovine trophectoderm (oTr1) cells cultured in vitro. Arg, but not Agm, increased proliferation and migration of oTr1 cells, but neither Arg nor Agm affected cell adhesion. The total amount of IFNT in culture medium of oTr1 cells was increased by Arg, but Agm increased the IFNT production per oTr1 cell. Arg and Agm plus Arg decreased secretion of dopamine and norepinephrine by oTr1 cells. Agm upregulates expression of mRNAs SLC7A1, Agmatinase and OAZ2 while the combination of Arg and Agm decreased expression of mRNAs for ODC1, SLC7A1, OAZ1 and OAZ3 by oTr1 cells. Although Agm does not stimulate proliferation, migration or adhesion of oTr1 cells or their secretion of catecholamines, Agm did increase transcription of SLC7A1, Agmatinase and OAZ2 genes which would increase the capacity of oTr1 cells to produce polyamines. Collectively, our findings suggest a role for Arg and Agm in the regulation of transport of basic amino acids (including Arg), polyamine synthesis, and secretion of catecholamines by oTr1 cells.
Sidney M. Morris - One of the best experts on this subject based on the ideXlab platform.
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Recent advances in arginine metabolism.
Current opinion in clinical nutrition and metabolic care, 2004Co-Authors: Sidney M. MorrisAbstract:Purpose of review Arginine metabolism has been a topic of intense interest over the past 15-20 years, primarily with regard to the role of arginine as the nitrogen donor for nitric oxide synthesis. However, other important aspects of arginine metabolism, such as arginine transport and arginine catabolism via the arginases, arginine decarboxylase or Agmatinase, have been less well studied. The purpose of this review is to highlight recent studies on the urea cycle, agmatine metabolism, and the arginases. Recent findings Recent advances include the cloning of complementary DNA encoding Agmatinase, N-acetylglutamate synthetase, and proteins involved in mitochondrial arginine transport, as well as initial investigations of their regulation and tissue-specific expression. The most exciting results of studies in this area over the past year or so have indicated new roles for the arginases in health and disease, as a result of their effects on the synthesis of nitric oxide, proline, or polyamines, or on the expression of specific genes by their ability to limit the availability of free arginine. Summary Recent studies have led to refinements in our understanding of the urea cycle. Agmatine metabolism is still largely a mystery, although the isolation of cloned cDNA for Agmatinase and possibly also arginine decarboxylase should stimulate much needed investigations in this area. The most exciting findings in the field are coming from studies indicating new roles for the arginases in various diseases.
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Vertebrate Agmatinases: What Role Do They Play in Agmatine Catabolism?
Annals of the New York Academy of Sciences, 2003Co-Authors: Sidney M. MorrisAbstract:Whereas agmatine in vertebrates may be derived from multiple sources such as the diet, endogenous synthesis via arginine decarboxylase, and possibly also from enteric bacteria, Agmatinase is the only enzyme specific for agmatine catabolism. As it hydrolyzes a guanidino group within agmatine and also contains signature amino acid residues that act as ligand binding sites for the Mn(++) cofactor, Agmatinase is classified as a member of the arginase superfamily. Very little information is available regarding how much agmatine in vertebrate species is catabolized by Agmatinase versus other enzymes such as diamine and amine oxidases. Moreover, comparisons of primary sequences of several vertebrate Agmatinases demonstrate that several residues essential for catalytic activity are not conserved in the mouse. This leads to the prediction that the Agmatinase protein in mouse has little or no catalytic activity, not only raising questions about the physiologic routes of agmatine disposal in this organism, but also suggesting the existence of species-specific differences in mechanisms for regulating agmatine levels.
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Cloning of human Agmatinase. An alternate path for polyamine synthesis induced in liver by hepatitis B virus
American journal of physiology. Gastrointestinal and liver physiology, 2002Co-Authors: Sanjay K. Mistry, Tim J. Burwell, Rebecca M. Chambers, Laura Rudolph-owen, Frank Spaltmann, W. Jim Cook, Sidney M. MorrisAbstract:Agmatinase, which hydrolyzes agmatine to putrescine and urea, not only represents a potentially important mechanism for regulating the biological effects of agmatine in mammalian cells but also rep...
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Cloning of human Agmatinase. An alternate path for polyamine synthesis induced in liver by hepatitis B virus
2002Co-Authors: Sanjay K. Mistry, Sidney M. Morris, Tim J. Burwell, Rebecca M. Chambers, Laura Rudolph-owen, Frank Spaltmann, Jim W. Cook, Sanjay K, Rebecca M. ChamAbstract:tinase. An alternate path for polyamine synthesis induced in liver by hepatitis B virus. Am J Physiol Gastrointest Liver Physiol 282: G375–G381, 2002; 10.1152/ajpgi.00386.2001.— Agmatinase, which hydrolyzes agmatine to putrescine and urea, not only represents a potentially important mechanism for regulating the biological effects of agmatine in mamma-lian cells but also represents an alternative to ornithine decarboxylase for polyamine biosynthesis. We have isolated a full-length cDNA encoding human Agmatinase whose func-tion was confirmed by complementation in yeast. The single-copy human Agmatinase gene located on chromosome 1 en-codes a 352-residue protein with a putative mitochondrial targeting sequence at the NH3-terminus. Human agmati-nase has about 30 % identity to bacterial Agmatinases and 20 % identity to mammalian arginases. Residues require
José Benítez - One of the best experts on this subject based on the ideXlab platform.
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Metabolic strategies for the degradation of the neuromodulator agmatine in mammals.
Metabolism, 2018Co-Authors: José Benítez, Mónica Salas, David García, Nicol Romero, Arlette González, Vasthi López, José Martínez-oyanedel, María De Los Ángeles García-robles, Maximiliano Figueroa, Peter R. DoddAbstract:Agmatine (1-amino-4-guanidinobutane), a precursor for polyamine biosynthesis, has been identified as an important neuromodulator with anticonvulsant, antineurotoxic and antidepressant actions in the brain. In this context it has emerged as an important mediator of addiction/satiety pathways associated with alcohol misuse. Consequently, the regulation of the activity of key enzymes in agmatine metabolism is an attractive strategy to combat alcoholism and related addiction disorders. Agmatine results from the decarboxylation of L-arginine in a reaction catalyzed by arginine decarboxylase (ADC), and can be converted to either guanidine butyraldehyde by diamine oxidase (DAO) or putrescine and urea by the enzyme Agmatinase (AGM) or the more recently identified AGM-like protein (ALP). In rat brain, agmatine, AGM and ALP are predominantly localised in areas associated with roles in appetitive and craving (drug-reinstatement) behaviors. Thus, inhibitors of AGM or ALP are promising agents for the treatment of addictions. In this review, the properties of DAO, AGM and ALP are discussed with a view to their role in the agmatine metabolism in mammals.
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Mammalian Agmatinases constitute unusual members in the family of Mn2+-dependent ureahydrolases.
Journal of inorganic biochemistry, 2016Co-Authors: Nicol Romero, José Benítez, David García, Arlette González, Vasthi López, Gerhard Schenk, María De Los Ángeles García-robles, Leonardo Bennun, Liam A. Wilson, Nelson CarvajalAbstract:Agmatine (1-amino-4-guanidinobutane) plays an important role in a range of metabolic functions, in particular in the brain. Agmatinases (AGMs) are enzymes capable of converting agmatine to the polyamine putrescine and urea. AGMs belong to the family of Mn-dependent ureahydrolases. However, no AGM from a mammalian source has yet been extracted in catalytically active form. While in human AGM the six amino acid ligands that coordinate the two Mn ions in the active site are conserved, four mutations are observed in the murine enzyme. Here, we demonstrate that similar to its human counterpart murine AGM does not appear to have in vitro catalytic activity, independent of the presence of Mn. However, in presence of agmatine both enzymes are very efficient in promoting cell growth of a yeast strain that is deficient in polyamine biosynthesis (Saccharomyces cerevisiae strain TRY104Δspe1). Furthermore, mutations among the putative Mn binding residues had no effect on the ability of murine AGM to promote growth of the yeast culture. It thus appears that mammalian AGMs form a distinct group within the family of ureahydrolases that (i) either fold in a manner distinct from other members in this family, or (ii) require accessory proteins to bind Mn in a mechanism related to that observed for the Ni-dependent urease.
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Cloning of two LIMCH1 isoforms: characterization of their distribution in rat brain and their Agmatinase activity
Histochemistry and Cell Biology, 2016Co-Authors: David García, Nelson Carvajal, José Benítez, Arlette González, Vasthi López, Patricio Ordenes, María A. García-robles, Elena UribeAbstract:Agmatine, a precursor for polyamine biosynthesis, is also associated with neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. This molecule results from the decarboxylation of l -arginine by arginine decarboxylase, and it is hydrolyzed to urea and putrescine by Agmatinase. Recently, we have described a new protein that also hydrolyzes agmatine, Agmatinase-like protein (ALP), which was identified through immunohistochemical analysis in the hypothalamus and hippocampus of rats. However, its sequence differs greatly from all known Agmatinases and does not contain the typical Mn^2+ ligands associated with the urea hydrolase family of proteins. ALP has a LIM-like domain close to its carboxyl terminus, and the removal of which results in a truncated variant with a tenfold increased k _cat value and a threefold decreased K _ m value for agmatine. Analysis of the gene database revealed several transcripts, denominated LIMCH1 isoforms, with extreme 3′ sequences identical to ALP. Limch1 gene products have been described as members of a multi-domain family of proteins with the biggest isoform containing a calponin homology (CH) domain at its N-terminus. Here, we cloned two LIMCH1 transcripts, one of 3177 bp and the other of 2709 bp (ALP contains 1569 bp) and analyzed LIMCH1 expression and distribution in rat brain using RT-PCR, Western blot and immunohistochemical analyses. LIMCH1 was detected mainly in the hypothalamic and hippocampal regions, which is similar to the distribution of ALP and agmatine in brain. In addition, we cloned and expressed both isoforms in E. coli and confirmed that they were catalytically active on agmatine with kinetic parameters similar to ALP. LIM domain-truncated variants of both isoforms moderately increased the k _cat and catalytic efficiency. Thus, we propose that LIMCH1 is useful to regulate the intracellular concentrations of the neurotransmitter/neuromodulator, agmatine.
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insight on the interaction of an Agmatinase like protein with mn2 activator ions
Journal of Inorganic Biochemistry, 2015Co-Authors: Matías Quiñones, Nelson Carvajal, Jaime Cofré, José Benítez, David García, Nicol Romero, Arlette González, María De Los Angeles García, Vasthi López, Gerhard SchenkAbstract:Agmatinase is an enzyme that catalyzes the hydrolysis of agmatine, a compound that is associated with numerous functions in the brain of mammalian organisms such as neurotransmitter, anticonvulsant, antinociceptive, anxiolytic and antidepressant-like actions. To date the only characterized Agmatinases with significant enzymatic activity were extracted from bacterial organisms. These Agmatinases are closely related to another ureahydrolase, arginase; both have binuclear Mn2+ centers in their active sites. An Agmatinase-like protein (ALP) from rat brain was identified that bears no sequence homology to known Agmatinases (E. Uribe, M. Salas, S. Enriquez, M.S. Orellana, N. Carvajal, Arch. Biochem. Biophys. 461(2007) 146-150). Since all known ureahydrolases contain histidines in their binuclear Mn2+ site each of the five histidine residues in ALP was individually replaced by alanines to identify those that may be involved in metal ion binding. Reactivation assays and thermal stability measurements indicated that His206 is likely to interact with a Mn2+ bound to a high affinity site. In contrast, His65 and possibly His435 are important for binding of a second Mn2+ to a lower affinity site. Metal ion binding to that site is not only leading to an increase in reactivity but also enzyme stability. Thus, similar to bacterial Agmatinases and some of the antibiotic-degrading, Zn2+-dependent metallo-beta-lactamases ALP appears to be active in the mono and binuclear form, with binding of the second metal ion increasing both reactivity and stability. (C) 2015 Elsevier Inc. All rights reserved.
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Insight on the interaction of an Agmatinase-like protein with Mn2 + activator ions
Journal of inorganic biochemistry, 2015Co-Authors: Matías Quiñones, Nelson Carvajal, Jaime Cofré, José Benítez, David García, Nicol Romero, Arlette González, María De Los Angeles García, Vasthi López, Gerhard SchenkAbstract:Agmatinase is an enzyme that catalyzes the hydrolysis of agmatine, a compound that is associated with numerous functions in the brain of mammalian organisms such as neurotransmitter, anticonvulsant, antinociceptive, anxiolytic and antidepressant-like actions. To date the only characterized Agmatinases with significant enzymatic activity were extracted from bacterial organisms. These Agmatinases are closely related to another ureahydrolase, arginase; both have binuclear Mn2+ centers in their active sites. An Agmatinase-like protein (ALP) from rat brain was identified that bears no sequence homology to known Agmatinases (E. Uribe, M. Salas, S. Enriquez, M.S. Orellana, N. Carvajal, Arch. Biochem. Biophys. 461(2007) 146-150). Since all known ureahydrolases contain histidines in their binuclear Mn2+ site each of the five histidine residues in ALP was individually replaced by alanines to identify those that may be involved in metal ion binding. Reactivation assays and thermal stability measurements indicated that His206 is likely to interact with a Mn2+ bound to a high affinity site. In contrast, His65 and possibly His435 are important for binding of a second Mn2+ to a lower affinity site. Metal ion binding to that site is not only leading to an increase in reactivity but also enzyme stability. Thus, similar to bacterial Agmatinases and some of the antibiotic-degrading, Zn2+-dependent metallo-beta-lactamases ALP appears to be active in the mono and binuclear form, with binding of the second metal ion increasing both reactivity and stability. (C) 2015 Elsevier Inc. All rights reserved.
