Action Pattern of Pectate Lyase fromStreptomyces nitrosporeus

Abstract

When polygalacturonic acid was degraded by the purified pectate lyase of Streptomyces nitrosporeus, unsaturated trigalacturonic acid was formed as the main end reaction product. Paper chromatographic analysis of reaction products showed that the enzyme cleaved polygalacturonate by a terminal mechanism. The attack sites of oligogalacturonates by the enzyme were only third bonds from the reducing ends of the molecular. Reduced poly- and pentagalacturonates with sodium borohydride were resistant to the action of the enzyme. From these results it has been shown that the pectate lyase of S. nitrosporeus is a new type exopolygalacturonate lyase removing terminally units of unsaturated trigalacturonic acid from the reducing ends of polygalacturonate chains.