Purification and some properties of an endocellular sucrase from a constitutive mutant of Bacillus subtilis Marburg 168.

Abstract

In Bacillus subtilis Marburg 168 an endocellular invertase‐like sucrase can be induced by sucrose. Sucrose, glucose and glycerol exert a catabolite repression on sucrase synthesis in both the inducible strain 168 and a constitutive derivative isolated in this laboratory. Derepressed cultures of this constitutive mutant grown on glutamate and succinate procedure high levels of sucrase and are utilized as starting material for the purification process.The purified preparation gives one single protein band after disc electrophoresis on polyacrylamide gel in the absence or in the presence of dodecylsulphate. This enzyme has a molecular weight of about 55000.Sucrase is not a glycoprotein, it is activated by potassium ions and inhibited by p‐hydroxymercuribenzoate. Arguments are presented in favour of the hypothesis that, in vivo, 6G‐phosphorylsucrose (6‐O‐phosphoryl‐α‐D‐glucopyranosyl‐1,2‐β‐d‐fructof uranoside) rather sucrose serves as a substrate for this enzyme.