Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A chromatographic-videodensitometric assay was found to be appropriate for measuring the activity of glutamate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, ornithine-2-oxoacid aminotransferase and histidine ammonia-lyase in human tissue homogenates. From the assay mixtures containing substrate(s), cofactor(s), buffer and tissue extract, five or ten microliters samples were taken at different time intervals and chromatographed on Dowex 50 X 8 type resin-coated chromatosheets. On each chromatoplate 50 nmoles of the amino acid to be measured were separately run as a reference for videodensitometric evaluation. By comparing the density of the reference amino acid to that of the individual samples the molar amount of amino acids formed or consumed in the reaction could be calculated. The present findings suggest that the chromatographic-videodensitometric microassay (CV-technique) is suitable for measuring the activity of amino acid transforming enzymes in minute amounts of tissue extracts.
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PMID:Determination of enzyme activity by chromatography and videodensitometry. I. Microassay of amino acid transforming enzymes in human tissue homogenates. 54 67

Effects of histidine deficiency on muscle carnosine and anserine levels and on activities of enzymes associated with histidine catabolism and protoporphyrin synthesis were investigated. Male Sprague-Dawley (150 g) rats were tube-fed isonitrogenous, isocaloric, defined diets containing 0%, low (0.013%) or adequate (0.45%) histidine for 8-13 days. While histidine-deficient animals maintained body weight, muscle and plasma histidine and carnosine concentrations decreased rapidly and remained low following a 3-day histidine repletion period. Hepatic histidine ammonia-lyase and histidine-pyruvate transaminase activities were decreased in histidine-deficient animals, whereas formiminotransferase activity was unchanged. Hematocrit levels and hemoglobin concentrations declined progressively during histidine depletion and the activity of erythrocyte and hepatic delta-aminolevulinic acid dehydratase also decreased relative to controls. Evidence is presented indicating that decreased histidine catabolism combined with carnosine and hemoglobin degradation can provide sufficient histidine to explain the slow onset of negative nitrogen balance associated with histidine deficiency and that impaired protoporphyrin synthesis may partially explain the anemia observed in the absence of dietary histidine.
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PMID:Metabolic effects of histidine-deficient diets fed to growing rats by gastric tube. 649 66