Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intraperitoneal administration to rats of D- or DL-alpha-hydrazinoimidazolylpropionic acid was found to produce a substantial inactivation of hepatic histidine ammonia-lyase (EC 4.3.1.3) in vivo. Proportional to this loss in enzyme activity was an impairment of the ability of treated rats to oxidize L-[ring-2-14C] histidine to 14CO2. Rats in which hepatic histidine ammonia-lyase activity was either depressed by DL-hydrazinoimidazolylproprionic acid injection or elevated by feeding a high protein diet displayed proportionately altered rates of 3H2O release into plasma water following L-[3-3H] histidine administration. Plasma L-histidine clearance following loading with this amino acid was similarly affected by these treatments. Administration of DL-alphal-hydrazinoimisazolylproprionic acid to rats was also found to inactivate non-specifically pyridoxal 5-phosphate enzymes in vivo; pyridoxine injection was found to reverse the DL-alpha-hydrazinoimidazolylproprionic acid-induced inactivation of hepatic aspartate aminotransferase (EC 2.6.1.1) in vivo, but not that of hepatic histidine ammonia-lyase. These findings demonstrate that histidine ammonia-lyase is the rate-limiting factor in L-histidine degradation in the rat. The potential usefulness of DL-hydrazinoimidazolylproprionic acid in the production of an animal model for histidinemia (hereditary histidine ammonia-lyase deficiency) is discussed.
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PMID:Studies on the production and assessment of experimental histidinemia in the rat. 0 33

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