PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Transaminases”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1976

Ornithine delta-transaminase activity in Escherichia coli: its identity with acetylornithine delta-transaminase.

Procedures that have been developed for the purification of acetylornithine delta-transaminase from Escherichia coli W also lead to the simultaneous purification of ornithine delta-transaminase. These two enzymatic activities have the same electrophoretic mobility and are identical immunochemically. Studies of inhibition kinetics demonstrate that the two substrates, acetylornithine and ornithine, compete for the same active site of acetylornithine delta-transaminase; thus, the ornithine delta-transaminase activity in E coli is due to acetylornithine delta-transaminase and not to a separate specific ornithine delta-transaminase.

Binding Sites↗
PubMed1976

Transaminase of branched chain amino acids. XI. Leucine (methionine) transaminase of rat liver mitochondria.

An aminotransferase (transaminase) which is active for leucine and methionine, but not for valine or isoleucine, was purified from rat liver mitochondria. The purified preparation appeared homogeneous on polyacrylamide disc gel electrophoresis. Its molecular weight was shown to be 55 000 by gel filtration. It differed from enzyme II (leucine aminotransferase, EC 2.6.1.6) in the supernatant fraction, another transaminase which is also specific for leucine and methionine, in molecular weight, Km values for substrates, electrophoretic mobility, chromatographic behavior and heat stability. From comparison with related transaminases it was concluded to be a new enzyme and named mitochondrial leucine (methionine) transaminase.

Animals↗
PubMed1978

Comparative study of miscellaneous properties of cysteine sulfinate transaminase and glutamate oxaloacetate transaminase in chick retina homogenate.

The activity, properties, and developmental pattern of cysteine sulfinate transaminase (CSA-T) were studied in chick retina and compared with the activity, properties, and developmental pattern of glutamate oxaloacetate transaminase (GOT). Their optimum pH is identical whereas the effect of pyridoxal phosphate seems to be different. Developmental patterns are also different. The Km and Vm of CSA-T and GOT were determined in chick retina homogenate. These results suggest that two different enzymes are responsible for the transamination of cysteine sulfinate (CSA) and aspartate.

Aging↗
PubMed1978

[Comparative high rising dose study of oral 17-alpha-ethinylestradiol (EE2), estriol (E3), and parenteral 16-alpha-17-beta-estrioldihemisuccinate (E3-suc) in their effects on serum levels of glutamate transaminase (GOT), pyruvate transaminase (GPT), leucine amino peptidase (LAP), alkaline phosphatase (AP), and bilirubin in 30 hysterectomized and ovarectomized women (author's transl)].

UNLABELLED: 30 hysterectomized and ovarectomized women were treated with three different estrogens: EE2 orally, E3 orally, and E3-suc intramuscularly. Each patient received one substance over 5 days doubling the dose every consecutive day, and switching to another estrogen after a treatment free interval of 2 days, rising the dosage of the second preparation twofold every consecutive day over another 5 days. Thus, each patient served as her own control with respect to 2 of the 3 tested estrogens. Six groups were required to test all sequences possible. The patients were allocated by random. GOT, GPT, LAP, AP and bilirubin were estimated daily over 2 weeks. The starting dose of EE2 was 0.25 mg, of E3 2 mg, and of E3-suc 2.5 mg. RESULTS: There were marked elevations of all serum enzymes during the week of EE2 treatment. If EE2 was given in the first week, and either E3 or E3-suc in the second one there was a prompt fall of all enzyme levels in spite of the approximately tenfold higher dose of the latter two estrogens. There were only minor elevations of the enzymes after oral E3 and parenteral E3-suc in some subjects and no differences of response between these two estrogens. Bilirubin reacted with an overall rise in the majority of patients irrespective of the type of estrogen.

Adult↗
PubMed1979

Serum glutamic oxalacetic transaminase, glutamic pyruvic transaminase, gamma-glutamyl transpeptidase and glutamic dehydrogenase levels in favism.

Serum GOT, GPT, gamma-GT and GLDH were determined in 15 G-6-PD-deficient subjects during a hemolytic crisis and hemoglobinuria due to ingestion of fresh fava beans. The same G-6-PD-deficient subjects were studied again 2 months after the crisis, when they were asymptomatic. 15 normal healthy children served as controls. A statistically significant increase, above normal, in serum GOT, GLDH and gamma-GT was observed in the favic subjects during the crisis. All the values reverted to normal in the asymptomatic period.

Alanine Transaminase↗
PubMed1991

Cytosolic L-alanine:4,5-dioxovalerate transaminase differs from the mitochondrial form.

L-Alanine:4,5-dioxovalerate transaminase was detected in the kidney cytosolic fraction with a lower specific activity than the mitochondrial enzyme. The enzyme was purified from the cytosol to homogeneity with a yield of 32%, and comparative analysis with the mitochondrial form was performed. Both forms of the enzyme have identical pH and temperature optima and also share common antigenic determinants. However, differences in their molecular properties exist. The molecular mass of the native cytoplasmic enzyme is 260 kDa, whereas that of the mitochondrial enzyme is 210 kDa. In addition, the cytoplasmic L-alanine: 4,5-dioxovalerate transaminase had a homopolymeric subunit molecular mass of 67 kDa compared to a subunit molecular mass of 50 kDa for the mitochondrial L-alanine:4,5-dioxovalerate transaminase. This is the first report of two forms of L-alanine:4,5-dioxovalerate transaminase. The different responses of cytosolic and mitochondrial L-alanine:4,5-dioxovalerate transaminases to hemin supplementation both in vitro and in vivo was demonstrated. Maximum inhibition of mitochondrial L-alanine:4,5-dioxovalerate transaminase activity was demonstrated with hemin injected at a dose of 1.2 mg/kg body mass, whereas the same dose of hemin stimulated the cytosolic enzyme to 150% of the control. A one-dimensional peptide map of partially digested cytosolic and mitochondrial L-alanine:4,5-dioxovalerate transaminase shows that the two forms of the enzymes are structurally related. Partial digestion of the cytosolic form of the enzyme with papain generated a fragment of 50 kDa which was identical to that of the undigested mitochondrial form (50 kDa). Moreover, papain digestion resulted in a threefold increase in cytosolic enzyme activity over the native enzyme, and such enhancement was comparable to the activity of the mitochondrial form of the enzyme. Therefore, we conclude that the cytosolic form of L-alanine: 4,5-dioxovalerate transaminase is different from the mitochondrial enzyme. Furthermore, immunoblot analysis indicated that the mitochondrial enzyme has antigenic similarity to the cytosolic enzyme as well as to the papain-digested cytosolic enzyme 50-kDa fragment.

Animals↗
PubMed1977

Two omega-amino acid transaminases from Bacillus cereus.

Bacillus cereus strain K-22 produced two distinct omega-amino acid transaminases, one catalyzing the transamination between beta-alanine and pyruvic acid and the other that between gamma-aminobutyric acid and alpha-ketoglutaric aic. The two enzymes were partially purified and separated from each other by various chromatographies. beta-Alanine:pyruvic acid transaminase and gamma-aminobutyric acid:alpha-ketoglutaric acid transaminase were induced by the addition of beta-alanine and gamma-aminobutyric acid, respectively, to the growth medium. beta-Alanine transaminase showed an optimum pH of 10.0 and optimum temperature of 35 degrees C, and its Km values for beta-alanine and pyruvic acid were both 1.1 mM. gamma-Aminobutyric acid, epsilon-aminocaproic acid, 2-aminoethylphosphonic acid, and propylamine showed about 30-40% of the activity of beta-alanine as amino donors, and oxalacetic acid was as good an amino acceptor as pyruvic acid. The optimum pH and temperature of gamma-aminobutyric acid transaminase were 9.0 and 50 degrees C, respectively, and its Km value for gamma-aminobutyric acid was 2.8 mM, while that for alpha-ketoglutaric acid was 2.3 mM. gamma-Aminobutyric acid and delta-aminovaleric acid were good amino donors but other omega-amino acids were virtually inactive with gamma-aminobutyric acid transaminase; alpha-ketoglutaric acid, and to a lesser extent glyoxylic acid, were active amino acceptors. Sulfhydryl reagents specifically activated gamma-aminobutyric acid transaminase.

4-Aminobutyrate Transaminase↗
PubMed1979

Microbial transaminase activities and their relationship with bovine rumen metabolites.

Two each adult male crossbred cattle and murrah buffalo were fed a diet of alfalfa hay, chopped wheat straw, and concentrate mixture. Total rumen transaminase activity of cattle was higher than that of buffalo. Rumen protozoal fractions showed higher total transaminase activity than bacterial fractions in both ruminant species. Besides generally studied glutamate oxalacetate transaminase and glutamate pyruvate transaminase, a large number of other microbial transaminases also have been detected in the rumen of both the ruminant species. Bacterial fractions of rumen liquor were devoid of transaminases utilizing tryptophan, threonine, and lysine as their substrates. Ruminal ammonia and nonprotein nitrogen were correlated positively with microbial transaminases in both species. Transamination reactions may be important for assimilation of ruminal ammonia to cellular proteins.

Alanine Transaminase↗
PubMed1991

Glutamine transaminase K and cysteine S-conjugate beta-lyase activity stains.

An activity stain to detect glutamine transaminase K subjected to nondenaturing polyacrylamide gel electrophoresis (ND-PAGE) was developed. The gel is incubated with a reaction mixture containing L-phenyl-alanine, alpha-keto-gamma-methiolbutyrate (alpha KMB), glutamate dehydrogenase, phenazine methosulfate (PMS) and nitroblue tetrazolium (NBT). Glutamine transaminase K catalyzes a transamination reaction between phenylalanine and alpha KMB. The resultant methionine is a substrate of glutamate dehydrogenase. The NADH formed in the oxidative deamination of methionine reacts with PMS and NBT to form a blue band on the surface of the gel coincident with glutamine transaminase K activity. Cysteine S-conjugate beta-lyase activity is detected in the gel by incubating the gel with a reaction mixture containing alpha KMB (to ensure maintenance of the enzyme in the pyridoxal 5'-phosphate form), S-(1,2-dichlorovinyl)-L-cysteine (DCVC), PMS, and NBT. The products of the lyase reaction interact with PMS and NBT to form a blue dye coincident with the lyase activity. In addition, a new assay procedure for measuring cysteine S-conjugate beta-lyase activity was devised. This procedure couples pyruvate formation from DCVC to the alanine dehydrogenase reaction. Preparations of purified rat kidney glutamine transaminase K yield a single protein band on ND-PAGE (apparent Mr approximately 95,000). This band coincides with both the cysteine S-conjugate beta-lyase and glutamine transaminase K activities. Activity staining showed that homogenates of rat kidney, liver, skeletal muscle, and heart possess a glutamine transaminase K/cysteine S-conjugate beta-lyase activity with an Rf value on ND-PAGE identical to that of purified rat kidney glutamine transaminase K.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Transaminase B from Escherichia coli: quaternary structure, amino-terminal sequence, substrate specificity, and absence of a separate valine-alpha-ketoglutarate activity.

Transaminase B (branched-chain amino acid aminotransferase, EC 2.6.1.42), the ilvE gene product, was purified to apparent homogeneity from an Escherichia coli K-12 strain which carries the ilvE gene both on the host chromosome and on a plasmid. The oligomeric structure of the enzyme, as determined by analytical ultracentrifugation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was confirmed to be that of a hexamer with a molecular weight of about 182,000 and apparently identical subunits. Cross-linking with dimethylsuberimidate yielded trimers, dimers, and monomers, but essentially no species of higher molecular weight. These results are consistent with a double-trimer arrangement of the subunits in native enzyme. The amino-terminal sequence was found to be: Gly Thr Lys Lys Ala Asp Tyr Ile (Trp) Phe Asn Gly (Thr) (Met) Val. Purified transaminase B catalyzed transamination between alpha-ketoglutarate and l-isoleucine, l-leucine, l-valine, and, to a lesser extent, l-phenylalanine and l-tyrosine, the latter reacting very sluggishly. The enzyme was free of aspartate transaminase and of transaminase C. The apparent K(m) values for the branched-chain alpha-ketoacids were smaller than those for the corresponding amino acids. The lowest K(m) was recorded for dl-alpha-keto-beta-methyl-n-valerate, and the highest was recorded for l-valine. The ratio of the valine- and isoleucine-alpha-ketoglutarate activities did not change significantly during purification, and both activities were quantitatively removed from crude extract by antibody raised against purified transaminase B. These observations argue against the existence of a separate valine-alpha-ketoglutarate transaminase. Anti-E. coli transaminase B antibody cross-reacted with crude extract from Salmonella typhimurium, but not with extract obtained from Pseudomonas aeruginosa.

Amino Acid Sequence↗
PubMed1975

Modulation of leucine transaminase activity by dietary means.

The specific activity of leucine transaminase was measured in supernatants of liver, skeletal muscle (gastrocnemius), and kidney homogenates obtained from fed, starved, and protein-deprived rats. After 12 h of starvation, there were slight reductions in leucine transaminase activity of both muscle and kidney tissues. When starvation was prolonged to 1 full day, the activity of this enzyme increased by approximately twofold in both muscle and kidney. Prolongation of fasting to 5 days resulted in an additional increase in specific activity of leucine transaminase in muscle. During the entire 5 days of starvation, leucine transaminase activity remained unaltered in liver of starved rats. Protein deprivation for 1 or 5 days resulted in significant reductions in specific activity of leucine transaminase in skeletal muscle. Protein deprivation did not produce a remarkable effect on the activity of this enzyme in kidney or liver tissue. The results of this study, together with those previously obtained, indicate that within our experimental conditions increased oxidation of leucine in skeletal muscle of starved rats is not initially related to an alteration in activity of leucine transaminase. When caloric deficiency is prolonged, the potential for transamination is also increased. These adaptive changes increase the ability of skeletal muscle to use leucine as a metabolic fuel.

Animals↗