| 摘要 |
PROBLEM TO BE SOLVED: To provide novel mutants or variants of s-GDH having significantly improved heat stability, specific activity and affinity to glucose in comparison with prior mutants having a substitution at position 348 with improved specificity.SOLUTION: Provided is a mutant of PQQ-dependent soluble glucose dehydrogenase (s-GDH; EC 1.1.5.2) having improved specificity for glucose as compared to maltose, and a substitution of threonine at position 348 by either glycine, alanine or serine, wherein said mutant additionally comprises: a) at least one mutation for improving the stability of the mutant; and b) one or more mutation(s) for improving the affinity of the mutant to glucose, the mutation for improving heat stability is selected from the group consisting of S146A; L187F; and T313D; the mutation for improving affinity to glucose is selected from the group consisting of L110H or Y; Q246H, M or N; Y333A; G339T; M341V; V349A or G; and V436P, where these positions correspond to the amino acid positions known from the A. calcoaceticus s-GDH wild-type sequence (SEQ ID NO:2), and the mutant has at least 90% sequence identity to SEQ ID NO:2.SELECTED DRAWING: None |
