Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new spectrophotometric procedure is described for determining glutamate-dependent activities of aspartate aminotransferase, alanine aminotransferase, and ornithine aminotransferase with NADPH-linked glutamate dehydrogenase (GDH) from nitrate-grown Stichococcus bacillaris. The algal NADPH-GDH is highly specific for oxoglutarate and can catalyze the reduction of this keto acid in the presence of high glutamate concentrations, and thus is suitable for the measurement of oxoglutarate produced in glutamate-dependent amino-transferase reactions. The alga produces large amounts of NADPH-GDH which can be adequately purified in a few simple steps. The purified enzyme can be stored at 4 degrees C for several weeks without any detectable loss of activity. The algal NADPH-GDH can also be used for the estimation of small amounts of oxoglutarate in aqueous extracts.
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PMID:A spectrophotometric procedure for measuring oxoglutarate and determining aminotransferase activities using nicotinamide adenine dinucleotide phosphate-linked glutamate dehydrogenase from algae. 255 50

Hepatocytes were aseptically isolated from either the periportal (pp; zone 1) or the perivenous (pv; zone 3) region by digitonin-collagenase perfusion and cultured on type I collagen for 4 to 9 days. In freshly isolated cells the pp:pv activity ratios of the acinar marker enzymes gamma-glutamyltranspeptidase (gamma-GT), alanine aminotransferase (ALAT) and glutamate dehydrogenase (GLDH) were 2.8, 1.6 and 0.76, respectively. During culture ALAT and GLDH activities gradually declined, but the pp-pv difference was retained for at least 4 days. In contrast, the difference in the gamma-GT activity was rapidly lost, due to its fast initial activation in pv cells. The initial 7-ethoxycoumarin O-deethylase (ECDE) activity was higher in pv cells; this difference was retained for several days of culture and was increased by induction in vitro with either phenobarbital (PB) or beta-naphthoflavone (beta NF). Although the basal UDP-glucuronyltransferase (UDPGT) activity with either p-nitrophenol (pNP) or hydroxybiphenyl (HBP) as substrate did not differ significantly, the in-vitro PB- or beta NF-induced activity was higher in pv cells. Both glucuronidation and sulfation of methylumbelliferone tended to be higher in pv cells. Glutathione S-transferase was initially significantly higher in pv cells and this difference was augmented after in vitro induction by PB or beta NF. After six days in culture all the observed pp-pv differences had disappeared. These results suggest that hepatocytes isolated from the perivenous region seem to maintain their initially higher capacity for phase I and phase II drug reactions during culture and also respond more strongly than periportal cells to in vitro induction.
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PMID:Drug metabolism by periportal and perivenous rat hepatocytes. Comparison of phase I and phase II reactions and their inducibility during culture. 256 12

The activities in serum of alkaline phosphatase, gamma-glutamyltransferase, glutamate dehydrogenase, glutamic pyruvic transaminase and cholinesterase were compared after complete biliary obstruction (CBO) and choledochocaval fistula (CCF) in the rat. CCF was used as a model of complete biliary retention without bile stasis and without increased pressure in the biliary tract. The increases in AP, GLDH and gamma-GT within 24-h post-op. show no difference between the two experimental groups. The conclusion is that the retention of biliary constituents alone is responsible for the increase in the levels of serum activity and that other conditions like bile stasis and increased pressure in the biliary tract do not play an important role in the pathogenesis of these alterations. The rise of GPT activity in CCF is of a lesser degree than in CBO.
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PMID:The serum activities of AP, gamma-GT, GLDH, GPT and CHE after complete biliary obstruction and choledochocaval fistula in the rat. 256 1

The activity of dipeptidyl aminopeptidase IV was studied in the sera of 378 hospitalized patients. The mean activity of dipeptidyl aminopeptidase IV was elevated significantly in patients with neoplasmata and hepatitis, but not in patients with liver cirrhosis. Significant correlations (p less than 0.001) existed with gamma-glutamyl transferase, glutamate dehydrogenase, alkaline phosphatase and leucine aminopeptidase. A significant correlation with lactate dehydrogenase existed only in patients with neoplasmata. Principal component analysis, performed with aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, leucine aminopeptidase, lactate dehydrogenase and dipeptidyl aminopeptidase IV, revealed correlations between the activities of aspartate aminotransferase and alanine aminotransferase, and between alkaline phosphatase and leucine aminopeptidase, but neither dipeptidyl aminopeptidase IV nor lactate dehydrogenase showed any correlation with either of these two groups. In lectin affinity chromatography with concanavalin A and wheat germ lectin sepharose, serum dipeptidyl aminopeptidase IV from liver cirrhosis patients showed the same binding pattern as that from healthy subjects. The activity and glycosylation of dipeptidyl aminopeptidase IV in serum and hepatic plasma membranes was investigated in rats, following the induction of hepatitis with galactosamine. In the serum, dipeptidyl aminopeptidase IV activity was elevated as early as 6 h after galactosamine injection, and the elevated activity persisted until the 7th day. At the same time dipeptidyl aminopeptidase IV activity was also elevated in the hepatic plasma membrane. Ninety eight percent of hepatic dipeptidyl aminopeptidase IV bound to concanavalin A as well as to wheat germ lectin and this value was unchanged during hepatitis. In the serum of control rats, 90% of dipeptidyl aminopeptidase IV bound to concanavalin A but only 39% to wheat germ lectin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Dipeptidyl aminopeptidase IV in hospitalized patients and in galactosamine hepatitis of the rat: Activity and lectin affinity chromatography in serum and hepatic plasma membranes]. 257 17

The activity of glutamate related enzymes and the concentration of glutamine, glutamate and gamma-amino n-butyric acid (GABA) were investigated in the cerebral cortex of rats, in different stages of insulin-induced hypoglycemia. Hypoglycemia was produced by intraperitoneal injection of insulin 0.05-100 units per kg body weight. The minimum required dose to produce irreversible severe hypoglycemia was 0.5 units/kg. In 85% of the cases an insulin induced hypoglycemic convulsion, was achieved 130-150 minutes after injection. Blood glucose levels during insulin induced seizures ranged between 8-15 mg%. In the range of 0.5-100 u insulin/kg the degree of hypoglycemia and the onset of convulsions were identical. The concentration of glutamine was significantly reduced during convulsive and postconvulsive stages. Glutamate and GABA concentrations were reduced significantly in all stages of insulin-induced hypoglycemia. The decrease in glutamine concentration was concurrent with an increase in the activity of its degradative enzyme, glutaminase. This was apparent at the preconvulsive, convulsive and postconvulsive stages. The activity of other enzymes related to energy production such as glutamate dehydrogenase (GDH), glutamate transaminase (GPT) and aspartate aminotransferase (AAT) were also increased. The activity of glutamine synthase (GS) was unaffected by hypoglycemia. Insulin induced changes in glutamine, glutamate and their related enzymes could not be attributed to convulsion since a similar pattern of changes was observed in the preconvulsive and postconvulsive stages, and no changes were detected following picrotoxin-induced seizures.
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PMID:Changes in the activity of glutamate related enzymes in cerebral cortex, during insulin-induced seizures. 257 18

Eight permanent human hepatocellular carcinoma (HHC) cell lines were established from 8 individual patients by the use of aspirated needle biopsy specimens (smaller than 0.1 ml in size). The cells grew in clustered form and retained intercellular junctions and canaliculi resembling bile canaliculi. The presence of secreted human alpha-fetoprotein and human albumin was detected in the cultured medium. Hepatitis B surface (HBs) antigen was not found on these cells. Implantation of the cells into athymic mice was followed by the growth of hepatocellular carcinomas and the appearance of human alpha-fetoprotein in the mouse serum. Chromosome analysis of three of the cell lines showed hyperdiploidy in two of them and hypotetraploidy in the other. Enzyme analyses of culture medium and cell homogenates have detected some enzymes characteristic of liver tissue such as gamma-glutamyl transferase, sorbital dehydrogenase, alkaline phosphatase, glutamate dehydrogenase, as well as aspartate and alanine transaminase. These tumor cells have been continuously maintained in culture for over 6 years with no significant changes observed.
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PMID:Culturing of human hepatocellular carcinoma. A simple and reproducible method. 257 38

The early stages of insulin-dependent diabetes mellitus are characterized by a selective inability to secrete insulin in response to glucose, coupled to a better response to nonnutrient secretagogues. The deficient glucose response may be a result of the autoimmune process directed toward the beta-cells. Interleukin-1 (IL-1) has been suggested to be one possible mediator of immunological damage of the beta-cells. In the present study we characterized the sensitivity of beta-cells to different secretagogues after human recombinant IL-1 beta (rIL-1 beta) exposure. Furthermore, experiments were performed to clarify the biochemical mechanisms behind the defective insulin response observed in these islets. Rat pancreatic islets were isolated and kept in tissue culture (medium RPMI-1640 plus 10% calf serum) for 5 days. The islets were subsequently exposed to 60 pM human recombinant IL-1 beta during 48 h in the same culture conditions as above and examined immediately after IL-1 exposure. The rIL-1 beta-treated islets showed a marked reduction of glucose-stimulated insulin release. Stimulation with arginine plus different glucose concentrations, and leucine plus glutamine partially counteracted the rIL-1 beta-induced reduction of insulin release. The activities of the glycolytic enzymes hexokinase, glucokinase, and glyceraldehyde 3-phosphate dehydrogenase, were similar in control and IL-1-exposed islets. Treatment with IL-1 also did not impair the activities of NADH+- and NADPH+-dependent glutamate dehydrogenase, glutamate-aspartate transaminase, glutamate-alanine transaminase, citrate synthase, and NAD+-linked isocitrate dehydrogenase. The oxidation of D-[6-14C]glucose and L-[U-14C]leucine were decreased by 50% in IL-1-treated islets. Furthermore, there was a significant decrease in the ratios of [2-14C]pyruvate oxidation/[1-14C]pyruvate decarboxylation and L-[U-14C]leucine oxidation/L-[1-14C]leucine decarboxylation, indicating that IL-1 decreases the proportion of generated acetyl-coenzyme-A residues undergoing oxidation. However, in the presence of IL-1 there was a significant increase in L-[U-14C]glutamate oxidation. These combined observations suggest that exposure to IL-1 induces a preferential decrease in glucose-mediated insulin release and mitochondrial glucose metabolism. This mitochondrial dysfunction seems to reflect an impairment in proximal steps of the Krebs cycle. It is conceivable that the IL-1-induced suppression and shift in islet metabolism can be an explanation for the beta-cell insensitivity to glucose observed in the early phases of human and experimental insulin-dependent diabetes mellitus.
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PMID:Differential sensitivity to beta-cell secretagogues in cultured rat pancreatic islets exposed to human interleukin-1 beta. 266 6

We assayed serum levels of certain enzymes and tumor markers in patients after transcatheter arterial embolization (TAE) to evaluate the effectiveness of this treatment. Twenty patients had hepatocellular carcinoma and two patients had metastases to the liver from colon cancer. Assays were first done immediately after TAE and were continued for the next 12 days. Glutamic oxaloacetic transaminase (GOT; EC 2.6.1.1, L-aspartate:2-oxoglutarate aminotransferase), glutamic pyruvic transaminase (GPT; EC 2.6.1.2, L-alanine:2-oxoglutarate aminotransferase), and lactate dehydrogenase (EC 1.1.1.27; (S)-lactate:NAD+ oxidoreductase) peaked 24 to 48 h after TAE and returned to the base lines in 7 to 10 days. Mitochondrial GOT (mGOT) and glutamate dehydrogenase (GLDH; EC 1.4.1.2, L-glutamate:NAD+ oxidoreductase) also peaked at the same time after TAE. alpha-Fetoprotein peaked 2 h after TAE and decreased to half of the baseline on day 7. Carcinoembryonic antigen peaked at 24 h and fell at 48 h only in the patients with colon cancer. The total amount of cytosolic GOT, GPT, mGOT, and GLDH released was correlated to the volume of the necrotic mass estimated by computed tomography scans. The correlation coefficients for mGOT and GLDH were r = 0.919 and r = 0.939 (both p less than 0.001), respectively. Assays of mGOT and GLDH may be useful to estimate the volume of the necrotic mass of a hepatoma or metastatic carcinoma in the liver.
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PMID:Changes in serum enzyme activity after transcatheter arterial embolization for hepatic neoplasm. 283 50

This study was prompted by the paradox of strong presence of mitochondria in an anaerobic protozoan, recently reclassified from the yeasts. Stemming from publication in 1911 to 1912, Blastocystis hominis has been generally accepted as a harmless intestinal yeast of humans, with short standardized textbook (parasitology) descriptions, even to the present day. Reports since 1967 have changed the classification of B. hominis from yeast to protozoan (Sarcodina), and this has been followed by interest in B. hominis-caused disease, resulting in documentation of disease in humans and other primates. In this study of B. hominis, the basic ultrastructure of the mitochondria was shown by thin-section electron microscopy to be identical to that of an archetypical mitochondrion. There were hundreds of them in large B. hominis cells (100 to 200 microns in diameter). Mitochondria were confined to a peripheral ring of cytoplasm bounded by the outer cell membrane (there is no cell wall) and the membrane of the large, spherical, organelle-free central body that constitutes 75% of the cell's volume. Mitochondria tended to surround the cell's usual two to four nuclei. Rhodamine 123 stained the mitochondria selectively, visualized by fluorescence microscopy. The cell was devoid of cytochromes. Addition of 0.1% cytochrome c to the growth medium increased utilization of glucose by 34% and that of lactate by 17%. Furthermore, it markedly increased the number of mitochondrion-filled cells. At higher concentrations, cytochrome c inhibited the growth of the cells. Despite the presence of large numbers of mitochondria, activities of the mitochondrial enzymes pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, isocitrate dehydrogenase, glutamate dehydrogenase, and cytochrome c oxidase were absent. Thus, the function of the mitochondria in B. hominis remains unknown. Considerable activities of aspartate aminotransferase and alanine aminotransferase were found. Aldolase activity was prominent. Pyruvate decarboxylase was present. Diaphorase and lactate dehydrogenase were detectable but in suspect quantities. Other missing enzymes were gamma glutamyl transpeptidase, alkaline phosphatase (a lysosomal marker), and creatine kinase isoenzymes.
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PMID:Biochemical and ultrastructural study of Blastocystis hominis. 283 9

The activities of aspartate and alanine transaminase, serine dehydratase, arginase, glutamate dehydrogenase, adenylate deaminase and glutamine synthetase were determined in the stomach and small intestine of developing rats. Despite the common embryonic origin of the intestine and stomach, their enzymes showed quite different activity levels and patterns of development, depending on their roles. Most enzyme activities were low during late intrauterine life and after birth, attaining adult levels with the change of diet at weaning. No arginase activity was found in the stomach and no changes were detected in adenylate deaminase in the stomach or intestine throughout the period studied. Alanine transaminase, serine dehydratase and, to some extent, glutamine synthetase levels, significantly higher in late intrauterine life, decreased after birth, suggesting that the foetal stomach has a transient ability to handle amino acids.
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PMID:Activities of amino acid metabolizing enzymes in the stomach and small intestine of developing rats. 286 86


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