Abstract
A dialyzed cell-free extract of a strain (SM-I) of Corynebacterium diphtheriae was found to catalyze transamination reactions between α-ketoglutarate, oxalacetate, pyruvate and various kinds of amino acids. No activities of the extracts were demonstrated in 18 reactions out of 42 tested with 15 amino acids and 3 kinds of keto acids. The most active transamination was of glutamate-oxalacetate followed by the aspartate-α-ketoglutarate reaction. No activity was detected in the asparate-pyruvate system. The rate of formation of glutamate from α-ketoglutarate and aspartate was considerably increased by the addition of pyridoxal phosphate to the dialyzed extracts. The optimal pH for the reaction was found to be around 7.2.
