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Role of coenzyme in aminotransferase turnover

Journal Article · · J. Biol. Chem.; (United States)
OSTI ID:7094384
The role of coenzyme in determining intracellular content of pyridoxal enzymes was assessed by analyzing effects of pyridoxine deficiency on the rapidly degraded, readily dissociable tyrosine aminotransferase (EC 2.6.1.5) and the slowly degraded, nondissociable alanine aminotransferase (EC 2.6.1.2) of rat liver. Synthesis of the tyrosine enzyme was reduced, leading to a decreased amount of this enzyme, much of which was present as active apoenzyme. Synthesis of alanine aminotransferase was unchanged but much of this enzyme was present as an inactive apoenzyme which retained immunological reactivity. Degradation rates of both enzymes (t/sub /sup 1///sub 2// about 1.5 h, tyrosine aminotransferase; about 3 days, alanine aminotransferase) were not changed in pyridoxine deficiency. Hence, interaction with coenzyme is not a significant determinant in intracellular degradation of these aminotransferases. Coenzyme dissociation and intracellular stability probably reflect structural features of the proteins which determine both properties.
Research Organization:
Oak Ridge National Lab., TN
OSTI ID:
7094384
Journal Information:
J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 252:14; ISSN JBCHA
Country of Publication:
United States
Language:
English

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