Alanine aminotransferase from Cucurbita moschata cotyledons

Abstract

Alanine aminotransferase increased in pumpkin cotyledons during germination with the greatest increase occurring in green cotyledons. The enzyme was found in the soluble fraction and was inhibited by NH2OH and p-chloromercuribenzoate. Pyridoxal phosphate and glutathione or dithiothreitol overcame die respective inhibition. Dialysis of the enzyme reduced enzyme activity but the activity was restored by the addition of pyridoxal phosphate. Alanine aminotransferase was proposed to play a major role in the synthesis of the alanine which occurs in pumpkin cotyledons during germination.