ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Tryptophan aminotransferase was purified from rat brain extracts. The purified enzyme had an isoelectric point at pH 6.2 and a pH optimum near 8.0. On electrophoresis the enzyme migrated to the anode. The enzyme was active with oxaloacetate or 2-oxoglutarate as amino acceptor but not with pyruvate, and utilized various L-amino acids as amino donors. With 2-oxoglutarate. the order of effectiveness of the L-amino acids was aspartate 〉 5-hydroxytryptophan 〉 tryptophan 〉 tyrosine 〉 phenylalanine. Aminotransferase activity of the enzyme towards tryptophan was inhibited by L-glutamate. Sucrose density gradient centrifugation gave a molecular weight of approx. 55,000. The enzyme was present in both the cytosol and synaptosomal cytosol, but not in the mitochondria. The isoelectrk focusing profile of tryptophan: oxaloacetate aminotransferase activity was identical with that of L-aspartate: 2-oxoglutarate aminotransferase (EC 2.6.1.1) activity, with both subcellular fractions.On the basis of these data, it is suggested that the enzyme is identical with the cytosol aspartate: 2-oxoglutarate aminotransferase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1976.tb00314.x
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