19] l-lysine transaminase from Flavobacterium lutescens

Abstract

This chapter provides an overview of L-lysine transaminase from Flavobacteriurn lutescens. L-Lysine-α-ketoglutarate 6-aminotransferase catalyzes the transamination of terminal amino group of L-lysine to α-ketoglutarate to produce Δ 1 -piperideine-6-carboxylate and L-glutamate. The enzyme is purified in a crystalline form from Flavobacterium lutescens. An improved purification method of the enzyme by affinity chromatography, subunit structures, and the stereochemical analysis of the enzyme reaction are described in the chapter. The affinity adsorbent used for purification of the enzyme is L-lysylacetamidododecyl-Sepharose 6B. Sepharose 6B is activated in a 10% (w/v) solution of CNBr (pH 10.5-11.0) at 4 ° . L-Lysine-α-ketoglutarate 6-aminotransferase from F. lutescens is composed of one each of four nonidentical subunits (A, B 1 , B 2 , and C). The molecular weights of the subunits are determined by three methods: sodium lauryl sulfate disc gel electrophoresis, sephadex G-75 column chromatography in the presence of 6 M guanidine-HCl, and equilibrium centrifugation in the presence of 8 M urea.