New proteolytic enzymes - obtd. by mutagenesis of genes encoding wild-type enzymes for improved properties in detergent applications

摘要

Enzyme prod. is claimed which comprises a mutant proteolytic enzyme, obtd. by expression of a gene encoding the enzyme having an aminoacid sequence which differs in aminoacid(s) from the wild-type enzyme, which mutant enzyme is characterised in that it shows improved properties for application in detergents. The gene may be derived from a wild-type gene of a strain selected from B. subtilis, B. licheniformis, B. amyloliquefaciens and Bacillus nov. spec. PB92. Also claimed is an enzyme prod. which comprises a mutant proteolytic enzyme characterised by showing improved properties for application in detergents as compared to the wild-type enzyme having the aminoacid sequence of PB92 protease and having a mutation at aminoacid(s) 116, 126, 127, 128, 160, 166, 169, 212 and 216. Also claimed are a mutant gene encoding the mutant proteolytic enzyme, an expression vector which comprises the mutant gene and a prokaryotic host strain transformed with the expression vector. Also claimed is a method for selecting a proteolytic enzyme having improved properties for application in detergents which comprises (a) mutagenising a cloned gene encoding a proteolytic enzyme or fragment, (b) isolating the obtd. mutant protease gene(s), (c) introducing the mutant protease gene(s) into a host strain for expression and prodn., (d) recovering the produced mutant protease and (e) identifying those mutant proteases having improved properties for application in detergents.