Pyridoxamine-alpha-keto acid transamination activity of aspartate apoaminotransferases

Yagi, T.; Kagamiyama, H.; Nozaki, M.

Biochemical and Biophysical Research Communications 107(3): 897-902

1982


ISSN/ISBN: 0006-291X
PMID: 6753838
Document Number: 191224
Pyridoxamine-.alpha.-keto acid transamination activities of homogeneous aspartate apoaminotransferases from various organisms were determined. Aspartate apoaminotransferases from pig heart cytosol and bakers' yeast utilized both oxalacetate and .alpha.-ketoglutarate as amino acceptors, while those from pig heart mitochondria and bacteria (Escherichia coli B and Pseudomonas striata) showed reactivity only toward oxalacetate. Specific activities of bacterial aspartate apoaminotransferases were very high compared to those of the yeast and animal apoenzymes. Phosphate and various anions, including sulfate, raised the pyridoxamine-.alpha.-keto acid transamination activity of all the aspartate apoaminotransferases examined. However, a high concentration of phosphate inhibited the reaction.

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