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Carreras J. - One of the best experts on this subject based on the ideXlab platform.
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Phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and enolase activity and Isoenzymes in lung, colon and liver carcinomas.
Nature Publishing Group, 2024Co-Authors: Durany N., Joseph J., Campo E., Molina R., Carreras J.Abstract:We have compared the levels of phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and enolase activities and the distribution of their Isoenzymes in normal colon, liver and lung tissues, and in colon, liver and lung adenocarcinoma, lung squamous cell carcinoma and lung carcinoid. All tumours presented higher phosphoglycerate mutase and enolase activities and lower 2,3-bisphosphoglycerate phosphatase activity than the normal tissues. No changes were observed in the phosphoglycerate mutase isoenzyme patterns analysed by cellulose acetate electrophoresis. All specimens contained mainly type BB isoenzyme, traces of type MB isoenzyme and no type MM isoenzyme. However, the tumours had decreased levels of 2,3-bisphosphoglycerate mutase and 2,3-bisphosphoglycerate mutase-phosphoglycerate mutase hybrid enzyme. Determined by agarose gel electrophoresis, alpha alpha-enolase was the isoenzyme predominant in normal lung, colon and liver tissue, although alpha gamma- and gamma gamma-enolase were also present in all tissues. In colon, liver and non-endocrine lung tumours, the proportions of alpha gamma- and gamma gamma-enolase decreased. In contrast, in carcinoid tumours of the lung, the proportions of these Isoenzymes increased
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Phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and creatine kinase activity and Isoenzymes in human brain tumours.
Nature Publishing Group, 2024Co-Authors: Durany N., Joseph J., Cruz-sánchez F. F., Carreras J.Abstract:The distribution of phosphoglycerate mutase (EC 5.4.2.1, PGM), 2,3-bisphosphoglycerate phosphatase (EC 3.1.3.13, BPGP) and creatine kinase (EC 2.7.3.2, CK) activity and Isoenzymes in various regions of adult human brain and in brain tumours (astrocytomas, anaplastic astrocytomas, glioblastomas and meningiomas) has been determined using electrophoresis. PGM and cytosolic CK exist in mammalian tissues as three Isoenzymes that result from the homodimeric and heterodimeric combinations of two subunits [types M (muscle) and B (brain)] coded by separated genes. In addition, a dimeric form and an octameric form of mitochondrial CK exist in mammals. Type BB-PGM was the major PGM isoenzyme found in normal brain, although type MB-PGM and type MM-PGM were also detected. All brain tumours possessed lower PGM activity than normal brain, and meningiomas showed higher BPGP activity. In astrocytic tumours, the proportion of type MB- and type MM-PGM decreased, and in meningiomas these Isoenzymes were not detected. Type BB-CK and mitochondrial CK were the only CK Isoenzymes detected in normal brain. Astrocytomas possessed lower CK activity than anaplastic astrocytomas and glioblastomas and, in addition, tended to possess lower CK content than normal brain. No qualitative changes of the normal CK isoenzyme pattern were observed in the tumours
M E De Broe - One of the best experts on this subject based on the ideXlab platform.
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the cytosolic glutathione s transferase Isoenzymes in the dog kidney cortex as compared with the corresponding mdck renal cell line
Biochimica et Biophysica Acta, 1996Co-Authors: Hilde H Bohets, M E De Broe, E J Nouwen, Paul J DierickxAbstract:Cytosolic glutathione S-transferase (GST) (EC 2.5.1.18) Isoenzymes of dog kidney and MDCK (an established dog renal cell line) were purified and studied. Specific GST activity was 248 and 317 nmol/min/mg protein, for dog and MDCK, respectively. Cytosolic GST was only partially purified by glutathione affinity chromatography, a substantial amount (43% and 84% for dog kidney and MDCK, respectively) of the GST activity was found in the flow-through fraction. Affinity bound GST was separated into 6 and 3 Isoenzymes by anionic chromatofocusing for dog and MDCK, respectively. Flow-through GST was purified by gel filtration, anion exchange chromatography and anionic chromatofocusing showing only one GST isoenzyme, with distinct features from the affinity bound GST, for both dog and MDCK. The Isoenzymes were characterized by their kinetic properties, subunit composition, specific substrates and inhibitors and immunoblot. The major dog GSTs (DII, DIV and DVI) correspond to the MDCK Isoenzymes (MI, MII and MIII). Comparable pI values, a comparable affinity towards GSH and comparable sensitivities towards the inhibitors N-ethylmaleimide (NEM), triphenyltin chloride, cibacron blue and hematin were observed for the corresponding Isoenzymes: DII and MI, DIV and MII, DVI and MIII. Co-electrophoresis showed that the subunit composition was identical for DII and MI, and for DIV and MII. Inhibitor and substrate sensitivities showed that the affinity bound GSTs belong to class pi and mu, the presence of class pi was confirmed by immunoblot analysis. One homodimeric GST isoenzyme was observed in the dog kidney and MDCK flow-through. Both dog and MDCK isoenzyme have a nearly neutral pI, a high affinity towards CDNB and an equal sensitivity towards triphenyltin chloride, cibacron blue and hematin. However, based on inhibitor studies and immunoblot, this isoenzyme could not be attributed to an identified GST class. The overall isoenzyme pattern of dog and MDCK affinity bound and flow through GST is comparable. The dog and MDCK affinity bound GSTs have similar characteristics and all belong to class mu or pi.
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interpretation and clinical significance of alkaline phosphatase isoenzyme patterns
Critical Reviews in Clinical Laboratory Sciences, 1994Co-Authors: V O Van Hoof, M E De BroeAbstract:Alkaline phosphatase (ALP, EC 3.1.3.1) is a membrane-bound metalloenzyme that consists of a group of true Isoenzymes, all glycoproteins, encoded for by at least four different gene loci: tissue-nonspecific, intestinal, placental, and germ-cell ALP. Through posttranslational modifications of the tissue-nonspecific gene, for example, through differences in carbohydrate composition, bone and liver ALP are formed. Nowadays, most commercially available methods for separating or measuring ALP Isoenzymes are easy to perform and sensitive and allow for reproducible and quantitative results. As more Isoenzymes and isoforms have been characterized, confusion has arisen due to the many different names they were given. For the sake of simplicity and because of structural analogies, we propose an alternative nomenclature for the ALP Isoenzymes and isoforms based on their structural characteristics: soluble, dimeric (Sol), anchor-bearing (Anch), and membrane-bound (Mem) liver, bone, intestinal, and placental ALP. Together with lipoprotein-bound liver ALP and immunoglobulin-bound ALP, these names largely fit the many forms of ALP one can encounter in human serum and tissues. The clinically relevant Isoenzymes are sol-liver, Mem-liver, lipoprotein-bound liver, and Sol-intestinal ALP in liver diseases, and Sol-bone and Anch-bone ALP in bone diseases. Many different isoenzyme patterns can be found in malignancies and renal diseases. This test provides the clinician with valuable information for diagnostic purposes as well as for follow-up of patients and monitoring of treatment. However, ALP isoenzyme determination will only provide clinically useful information if the patterns are correctly interpreted. In this respect, care should be taken to use the proper reference ranges, taking into account the age and sex of the patient. A normal total ALP activity does not rule out the presence of an abnormal isoenzyme pattern, particularly in children. Separating ALP into its Isoenzymes adds considerable value to the mere assay of total ALP activity.
Tingkai Li - One of the best experts on this subject based on the ideXlab platform.
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purification and partial amino acid sequence of a high activity human stomach alcohol dehydrogenase
Alcoholism: Clinical and Experimental Research, 1993Co-Authors: Carol L Stone, Holly R Thomasson, William F Bosron, Tingkai LiAbstract:To understand the relative importance of alcohol dehydrogenase (ADH) Isoenzymes in gastric ethanol metabolism, a stomach-specific ADH (σ-ADH) was purified to homogeneity from human transplant donor and surgical tissues, and its activity for ethanol oxidation was examined. The enzyme from these tissues had a specific activity at pH 10 of ˜70 units/mg, about 10 times that reported by Moreno and Pares (J. Biol. Chem. 266:1128–1133, 1991). The enzyme exhibited a high Km for ethanol at pH 7.5 and 10 (29 and 5.2 mM, respectively). This high-activity α-ADH isoenzyme migrated on starch and isoelectric focusing gels to a position slightly anodic to the liver σ isoenzyme. It was subjected to digestion by endoproteinases, and ˜40% of the protein was sequenced. The σ-ADH exhibited 75%, 68%, and 62% sequence identity to the human class I (β1), II (π), and III (χ) Isoenzymes, respectively, and 61% identity to the deduced ADH6 amino acid sequence. Phylogenetic analysis indicated that precursors to this high-activity σ-ADH and the class I Isoenzymes diverged more recently than precursors to the class II and III Isoenzymes, after reptilian and avian divergence. The high-activity σ-ADH isoenzyme therefore represents a distinct class of ADH (class IV), more closely related in evolution to the class I Isoenzymes than to the other known human Isoenzymes.
Durany N. - One of the best experts on this subject based on the ideXlab platform.
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Phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and enolase activity and Isoenzymes in lung, colon and liver carcinomas.
Nature Publishing Group, 2024Co-Authors: Durany N., Joseph J., Campo E., Molina R., Carreras J.Abstract:We have compared the levels of phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and enolase activities and the distribution of their Isoenzymes in normal colon, liver and lung tissues, and in colon, liver and lung adenocarcinoma, lung squamous cell carcinoma and lung carcinoid. All tumours presented higher phosphoglycerate mutase and enolase activities and lower 2,3-bisphosphoglycerate phosphatase activity than the normal tissues. No changes were observed in the phosphoglycerate mutase isoenzyme patterns analysed by cellulose acetate electrophoresis. All specimens contained mainly type BB isoenzyme, traces of type MB isoenzyme and no type MM isoenzyme. However, the tumours had decreased levels of 2,3-bisphosphoglycerate mutase and 2,3-bisphosphoglycerate mutase-phosphoglycerate mutase hybrid enzyme. Determined by agarose gel electrophoresis, alpha alpha-enolase was the isoenzyme predominant in normal lung, colon and liver tissue, although alpha gamma- and gamma gamma-enolase were also present in all tissues. In colon, liver and non-endocrine lung tumours, the proportions of alpha gamma- and gamma gamma-enolase decreased. In contrast, in carcinoid tumours of the lung, the proportions of these Isoenzymes increased
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Phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and creatine kinase activity and Isoenzymes in human brain tumours.
Nature Publishing Group, 2024Co-Authors: Durany N., Joseph J., Cruz-sánchez F. F., Carreras J.Abstract:The distribution of phosphoglycerate mutase (EC 5.4.2.1, PGM), 2,3-bisphosphoglycerate phosphatase (EC 3.1.3.13, BPGP) and creatine kinase (EC 2.7.3.2, CK) activity and Isoenzymes in various regions of adult human brain and in brain tumours (astrocytomas, anaplastic astrocytomas, glioblastomas and meningiomas) has been determined using electrophoresis. PGM and cytosolic CK exist in mammalian tissues as three Isoenzymes that result from the homodimeric and heterodimeric combinations of two subunits [types M (muscle) and B (brain)] coded by separated genes. In addition, a dimeric form and an octameric form of mitochondrial CK exist in mammals. Type BB-PGM was the major PGM isoenzyme found in normal brain, although type MB-PGM and type MM-PGM were also detected. All brain tumours possessed lower PGM activity than normal brain, and meningiomas showed higher BPGP activity. In astrocytic tumours, the proportion of type MB- and type MM-PGM decreased, and in meningiomas these Isoenzymes were not detected. Type BB-CK and mitochondrial CK were the only CK Isoenzymes detected in normal brain. Astrocytomas possessed lower CK activity than anaplastic astrocytomas and glioblastomas and, in addition, tended to possess lower CK content than normal brain. No qualitative changes of the normal CK isoenzyme pattern were observed in the tumours
Johann Hofmann - One of the best experts on this subject based on the ideXlab platform.
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the potential for isoenzyme selective modulation of protein kinase c
The FASEB Journal, 1997Co-Authors: Johann HofmannAbstract:Protein kinase C (PKC) is a phospholipid-dependent serine/threonine kinase family consisting of at least 11 closely related Isoenzymes. The different PKC Isoenzymes play important roles in signal transduction pathways. The exact significance of each isoenzyme is not known at present; therefore, the elucidation of the roles of the various PKC Isoenzymes is important. To explain the function of distinct PKC Isoenzymes, the availability of isoenzyme-specific inhibibitors or activators would be an advantage. PKC inhibitors have been known for some time, but these compounds are not isoenzyme-specific and also inhibit other kinases. Recently, an inhibitor selective for PKC alpha and another one selective for PKCbetaI and betaII were described. Both compounds compete with the ATP binding sites that exhibit high homologies among the different PKC Isoenzymes. Among others, the phosporyl transfer region, the pseudosubstrate domain, the phorbolester binding sequences, and the phosphorylation sites may also be target...
