Purification and Some Properties of L-Serine Dehydratase of Corynebacterium sp.

Abstract

L-Serine dehydratase (L-Serine hydro-lyase, deaminating, EC 4. 2. 1. 13) was purified from Corynebacterium sp. (ATCC 21050) about 100 fold by the methods including (NH₄)₂SO₄ fractionation, heat treatment, DEAE-cellulose chromatography and hydroxyapatite chromatography. The purified enzyme has shown the highest specific activity yet reported. It acted only on L-serine and was inhibited by L-cysteine, L-alanine, D-serine and L-tryptophan and was activated by MgCl₂. The optimal pH for the enzymatic activity was 9.0. The substrate saturation curves of the enzyme showed a sigmoidal shape and a further examination revealed an evidence of homotropic substrate interactions which were both pH- and Mg²⁺ concentration-dependent. These suggested that L-serine dehydratase from Corynebacterium is a kind of allosteric enzyme.