Effect of pyridoxal 5'-phosphate on the activity of aspartate aminotransferase isoenzyme in human plasma after physical exercise.

Untrained healthy male volunteers were subjected to the study of the effects of physical exercise (bicycle ergometer, 150 W for 30 min) upon the activities of aspartate aminotransferase (AST [GOT]) isoenzymes, soluble and mitochondrial (AST-s and AST-m) with and without reactivation by the co-enzyme pyridoxal 5'phosphate (PALP) in plasma. Blood samples were drawn at the beginning and end of the exercise periods and then 20 min, and 1, 6, 24 and 48 hours later. There was a marked increase in AST-m activity with reactivation by PALP immediately after the exercise, whereas AST-s activity activated with PALP did not vary substantially. Inversely, a significant increase in AST-s activity with PALP added was observed at 48 hours after the exercise, but not in AST-m with PALP added. The changes in the effects of PALP on the activities of AST isoenzymes after physical exercise are discussed.