Purification and Properties of Pectate Lyase Produced byStreptomyces nitrosporeus

Abstract

A pectate lyase was purified from the culture filtrate of Streptomyces nitrosporeus by column chromatography on QAE-Sephadex A-50 and gelfiltration on Sephadex G-100. The purified enzyme was demonstrated to be homogeneous by disc electrophoresis. The optimum pH for the activity was 9.3 to 9.5 and the enzyme required calcium ions for maximum activity. The initial reaction rate was higher on partially esterified pectin than on polygalacturonic acid. The enzyme was more specific for tetra-, penta-, and hexagalacturonic acids than for polygalacturonic acid. But di- and trigalacturonic acids were not good substrates for the enzyme. The Km values of the enzyme for tri-, tetra-, penta-, hexagalacturonic acids and acid soluble polygalacturonic acid at 1.0 mm calcium ion concentration were 1.5, 0.19, 0.23, 0.38 mm and 0.051%, respectively.