Activities of arginase, transamidinase, and ornithine aminotransferase in glia, neurons, and synaptosomes.
The regional, cellular, and subcellular distribution of some enzymes of the urea cycle in brain is not clearly known. Glia, neurons, and synaptosomes have been prepared from rat cerebral cortex and arginase (EC 3.5.3.1), transamidinase (EC 2.1.4.1), and ornithine aminotransferase (EC 2.6.1.13) have been estimated in order to understand the metabolic and functional role of these enzymes. It has been observed that arginase is predominantly localized in synaptosomes and neurons. The ornithine aminotransferase was found to be high in glial cells and very high in synaptosomes (higher than arginase). Transamidinase was mostly localized in glial cells. The implication of these results has been discussed in relation to a possible role of ornithine acting as a precursor of glutamate in glutametargic nerve endings and its possible participation in the glutamate-glutamine cycle.
D000217:Acyltransferases / Q000378:metabolism*; D019881:Aminoacyltransferases; D000818:Animals; D001119:Arginase / Q000378:metabolism*; D001921:Brain / Q000201:enzymology; D009457:Neuroglia / Q000201:enzymology*; D009474:Neurons / Q000201:enzymology*; D009953:Ornithine-Oxo-Acid Transaminase / Q000378:metabolism*; D051381:Rats; D013574:Synaptosomes / Q000201:enzymology*; D014018:Tissue Distribution; D000637:Transaminases / Q000378:metabolism*
D000217:Acyltransferases; D019881:Aminoacyltransferases; C023175:transamidases; D000637:Transaminases; D009953:Ornithine-Oxo-Acid Transaminase; D001119:Arginase