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Doreen Dobritzsch - One of the best experts on this subject based on the ideXlab platform.
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yeast beta alanine synthase shares a structural scaffold and origin with dizinc dependent Exopeptidases
Journal of Biological Chemistry, 2003Co-Authors: Stina Lundgren, Jure Piškur, Zoran Gojkovic, Doreen DobritzschAbstract:Abstract β-Alanine synthase (βAS) is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of pyrimidine bases, including several anticancer drugs. In eukaryotes, βASs belong to two subfamilies, which exhibit a low degree of sequence similarity. We determined the structure of βAS from Saccharomyces kluyveri to a resolution of 2.7 A. The subunit of the homodimeric enzyme consists of two domains: a larger catalytic domain with a dizinc metal center, which represents the active site of βAS, and a smaller domain mediating the majority of the intersubunit contacts. Both domains exhibit a mixed α/β-topology. Surprisingly, the observed high structural homology to a family of dizinc-dependent Exopeptidases suggests that these two enzyme groups have a common origin. Alterations in the ligand composition of the metal-binding site can be explained as adjustments to the catalysis of a different reaction, the hydrolysis of an N-carbamyl bond by βAS compared with the hydrolysis of a peptide bond by Exopeptidases. In contrast, there is no resemblance to the three-dimensional structure of the functionally closely related N-carbamyl-d-amino acid amidohydrolases. Based on comparative structural analysis and observed deviations in the backbone conformations of the eight copies of the subunit in the asymmetric unit, we suggest that conformational changes occur during each catalytic cycle.
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yeast beta alanine synthase shares a structural scaffold and origin with dizinc dependent Exopeptidases
Journal of Biological Chemistry, 2003Co-Authors: Stina Lundgren, Jure Piškur, Zoran Gojkovic, Doreen DobritzschAbstract:beta-Alanine synthase (beta AS) is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of pyrimidine bases, including several anticancer drugs. In eukaryotes, beta ASs belong to two subfamilies, which exhibit a low degree of sequence similarity. We determined the structure of beta AS from Saccharomyces kluyveri to a resolution of 2.7 A. The subunit of the homodimeric enzyme consists of two domains: a larger catalytic domain with a dizinc metal center, which represents the active site of beta AS, and a smaller domain mediating the majority of the intersubunit contacts. Both domains exhibit a mixed alpha/beta-topology. Surprisingly, the observed high structural homology to a family of dizinc-dependent Exopeptidases suggests that these two enzyme groups have a common origin. Alterations in the ligand composition of the metal-binding site can be explained as adjustments to the catalysis of a different reaction, the hydrolysis of an N-carbamyl bond by beta AS compared with the hydrolysis of a peptide bond by Exopeptidases. In contrast, there is no resemblance to the three-dimensional structure of the functionally closely related N-carbamyl-d-amino acid amidohydrolases. Based on comparative structural analysis and observed deviations in the backbone conformations of the eight copies of the subunit in the asymmetric unit, we suggest that conformational changes occur during each catalytic cycle.
Birgitta Tomkinson - One of the best experts on this subject based on the ideXlab platform.
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tripeptidyl peptidase ii update on an oldie that still counts
Biochimie, 2019Co-Authors: Birgitta TomkinsonAbstract:The huge Exopeptidase, tripeptidyl-peptidase II (TPP II), appears to be involved in a large number of important biological processes. It is present in the cytosol of most eukaryotic cells, where it ...
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characterization of the endopeptidase activity of tripeptidyl peptidase ii
Biochemical and Biophysical Research Communications, 2012Co-Authors: Sandra Eklund, Jakob Dogan, Per Jemth, Hubert Kalbacher, Birgitta TomkinsonAbstract:Abstract Tripeptidyl-peptidase II (TPP II) is a giant cytosolic peptidase with a proposed role in cellular protein degradation and protection against apoptosis. Beside its well-characterised Exopeptidase activity, TPP II also has an endopeptidase activity. Little is known about this activity, and since it could be important for the physiological role of TPP II, we have investigated it in more detail. Two peptides, Nef69–87 and LL37, were incubated with wild-type murine TPP II and variants thereof as well as TPP II from human and Drosophila melanogaster. Two intrinsically disordered proteins were also included in the study. We conclude that the endopeptidase activity is more promiscuous than previously reported. It is also clear that TPP II can attack longer disordered peptides up to 75 amino acid residues. Using a novel FRET substrate, the catalytic efficiency of the endopeptidase activity could be determined to be 5 orders of magnitude lower than for the Exopeptidase activity.
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structure function and evolution of a giant enzyme tripeptidyl peptidase ii
2012Co-Authors: Sandra Eklund, Birgitta TomkinsonAbstract:Tripeptidyl-peptidase II (TPP II) is a giant Exopeptidase with an active site of the subtilisin-type. Its main function is to remove tripeptides from a free N-terminal end of longer peptides. TPP I ...
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association and dissociation of the tripeptidyl peptidase ii complex as a way of regulating the enzyme activity
Archives of Biochemistry and Biophysics, 2000Co-Authors: Birgitta TomkinsonAbstract:Abstract Tripeptidyl-peptidase II is an unusually large Exopeptidase. The subunits (Mr = 138,000) form an active complex with an Mr > 106. This paper demonstrates that the complex can spontaneously dissociate in vitro into dimers which retain 1 10 th of the original specific activity. The dissociated enzyme can reassociate at elevated temperatures, provided the protein concentration is sufficiently high. This reassociation was accompanied by a reactivation. The rate of reactivation was increased by the presence of competitive peptide inhibitors. It is speculated that association/dissociation may be a way of regulating the enzyme activity in vivo.
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structure function studies of recombinant murine tripeptidyl peptidase ii the extra domain which is subject to alternative splicing is involved in complex formation
FEBS Letters, 1997Co-Authors: Birgitta Tomkinson, Marete Hansen, Wingfai CheungAbstract:Tripeptidyl-peptidase II (TPP II) is an Exopeptidase with a remarkably high native Mr (> 106). Recently, an alternatively spliced, murine cDNA variant was identified which contains an additional 39 bp, encoding 13 aniino acids in the C- terminal end of the protein. The two enzyme variants were expressed in human kidney 293 cells. Both types of subunit were found to form the active oligomers. In addition, subunits containing the extra 13 amino acids formed an even larger complex eluting in the void volume of a Sepharose CL-4B column. Thus, it appears that this sequence is important for aggregation of subunits. © 1997 Federation of European Biochemical Societies.
Stina Lundgren - One of the best experts on this subject based on the ideXlab platform.
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yeast beta alanine synthase shares a structural scaffold and origin with dizinc dependent Exopeptidases
Journal of Biological Chemistry, 2003Co-Authors: Stina Lundgren, Jure Piškur, Zoran Gojkovic, Doreen DobritzschAbstract:Abstract β-Alanine synthase (βAS) is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of pyrimidine bases, including several anticancer drugs. In eukaryotes, βASs belong to two subfamilies, which exhibit a low degree of sequence similarity. We determined the structure of βAS from Saccharomyces kluyveri to a resolution of 2.7 A. The subunit of the homodimeric enzyme consists of two domains: a larger catalytic domain with a dizinc metal center, which represents the active site of βAS, and a smaller domain mediating the majority of the intersubunit contacts. Both domains exhibit a mixed α/β-topology. Surprisingly, the observed high structural homology to a family of dizinc-dependent Exopeptidases suggests that these two enzyme groups have a common origin. Alterations in the ligand composition of the metal-binding site can be explained as adjustments to the catalysis of a different reaction, the hydrolysis of an N-carbamyl bond by βAS compared with the hydrolysis of a peptide bond by Exopeptidases. In contrast, there is no resemblance to the three-dimensional structure of the functionally closely related N-carbamyl-d-amino acid amidohydrolases. Based on comparative structural analysis and observed deviations in the backbone conformations of the eight copies of the subunit in the asymmetric unit, we suggest that conformational changes occur during each catalytic cycle.
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yeast beta alanine synthase shares a structural scaffold and origin with dizinc dependent Exopeptidases
Journal of Biological Chemistry, 2003Co-Authors: Stina Lundgren, Jure Piškur, Zoran Gojkovic, Doreen DobritzschAbstract:beta-Alanine synthase (beta AS) is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of pyrimidine bases, including several anticancer drugs. In eukaryotes, beta ASs belong to two subfamilies, which exhibit a low degree of sequence similarity. We determined the structure of beta AS from Saccharomyces kluyveri to a resolution of 2.7 A. The subunit of the homodimeric enzyme consists of two domains: a larger catalytic domain with a dizinc metal center, which represents the active site of beta AS, and a smaller domain mediating the majority of the intersubunit contacts. Both domains exhibit a mixed alpha/beta-topology. Surprisingly, the observed high structural homology to a family of dizinc-dependent Exopeptidases suggests that these two enzyme groups have a common origin. Alterations in the ligand composition of the metal-binding site can be explained as adjustments to the catalysis of a different reaction, the hydrolysis of an N-carbamyl bond by beta AS compared with the hydrolysis of a peptide bond by Exopeptidases. In contrast, there is no resemblance to the three-dimensional structure of the functionally closely related N-carbamyl-d-amino acid amidohydrolases. Based on comparative structural analysis and observed deviations in the backbone conformations of the eight copies of the subunit in the asymmetric unit, we suggest that conformational changes occur during each catalytic cycle.
Minsoo Heu - One of the best experts on this subject based on the ideXlab platform.
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debittering of enzymatic hydrolysate using Exopeptidase active fractions from the argentina shortfin squid illex argentinus hepatopancreas
Korean Journal of Fisheries and Aquatic Sciences, 2014Co-Authors: Jinsoo Kim, Minji Kim, Kihyun Kim, Sang In Kang, Sung Hwan Park, Hyun Ji Lee, Minsoo HeuAbstract:Exopeptidase active fractions from the hepatopancreas of the Argentina shortfin squid Illex argentinus, were obtained with acetone (AC 30-40%), ammonium sulfate (AS 60-70% saturation), anion exchange chromatography (AE-II, 0.2 M NaCl) and gel filtration chromatography (GF-I, 30-50 kDa) fractionation methods. A bitter peptide solution that has a bitterness equivalent to that of 2% glycylphenylalanine and prepared by tryptic hydrolysis of milk casein, was treated with the Exopeptidase active fractions. The GF -I fraction was the best based on aminopeptidase activity (35.3 U/mg), percentage of recovery (30.7%) and a sensory evaluation (1.7). The amount of released amino acids increased as incubation time increased, and the bitterness of the enzyme reaction mixtures decreased. Incubation with the GF-I fraction for 24 h resulted in the hydrolysis of several peptides as revealed by the reverse-phase high performance liguid chromatography profile, with three peaks (3, 5 and 6) decreasing in area (%) and three peaks (1, 2 and 4) increasing in area (%). Therefore, the GF-I fraction appeared to be ideally suited to reduce bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.
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fractionation of Exopeptidase from viscera of argentina shortfin squid illex argentinus
Journal of The Korean Society of Food Science and Nutrition, 2008Co-Authors: Hyesuk Kim, Jinsoo Kim, Minsoo HeuAbstract:For the effective use of Exopeptidase from squid viscera as food processing aids, the viscera of Argentina shortfin squid (Illex argentinus) were fractionated by various methods such as acetone treatment, ammonium sulfate treatment, anion exchange chromatography, and gel filtration. The positive Exopeptidase fractions were obtained from the fraction II treated by cold acetone (, w/w), the fraction V by ammonium sulfate ( saturation), the fraction II (0.2 M NaCl) by anion exchange chromatography, and the fraction I () by gel filtration. The specific activities of positive fractions from viscera of I llex argentinus against substrates were higher to LeuPNA than to ArgPNA. Total activity and recovery against LeuPNA of positive fraction by gel filtration were 1,867 U and 30.69%, respectively, which were the highest among those of positive fraction. The results suggested that the gel filtration chromatography method was the most efficient method for the fractionation of Exopeptidase from viscera of Illex argentinus.
Neomal S Sandanayake - One of the best experts on this subject based on the ideXlab platform.
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identification of potential serum peptide biomarkers of biliary tract cancer using maldi ms profiling
BMC Clinical Pathology, 2014Co-Authors: Stephane Camuzeaux, Neomal S Sandanayake, Michael H. Chapman, George Webster, Oleg Blyuss, Ross C Smith, John Sinclair, Fausto Andreola, John F. TimmsAbstract:Background The aim of this discovery study was the identification of peptide serum biomarkers for detecting biliary tract cancer (BTC) using samples from healthy volunteers and benign cases of biliary disease as control groups. This work was based on the hypothesis that cancer-specific Exopeptidases exist and that their activities in serum can generate cancer-predictive peptide fragments from circulating proteins during coagulation.
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Identification of potential serum peptide biomarkers of biliary tract cancer using MALDI MS profiling.
2014Co-Authors: Neomal S Sandanayake, Camuzeaux S, Sinclair J, Blyuss O, Andreola F, Mh Chapman, Gj Webster, Rc Smith, Jf Timms, Sp PereiraAbstract:The aim of this discovery study was the identification of peptide serum biomarkers for detecting biliary tract cancer (BTC) using samples from healthy volunteers and benign cases of biliary disease as control groups. This work was based on the hypothesis that cancer-specific Exopeptidase activities in serum can generate cancer-predictive peptide fragments from circulating proteins during coagulation