title: [Site-directed mutagenesis and effects on the enzymatic properties of subtilisin E].
abstract: Site-directed mutagenesis was used to investigate the effects of S221C/P225A, N118S/S221C/P225A, D60N/N118S/S221C/P225A and Q103R/N118S/S221C/P225A mutations on the properties of Subtilisin E. It was found that S221C/P225A mutant is 73,000-fold decreased in amidase activity than subtilisin E and 3-fold increased than subtiligase in the ratio of esterase/amidase; N118S/S221C/P225A mutant has 3.6-fold and 15-fold decreased in amidase and esterase activity respectively and as a result, it has a 4-fold lower in the ratio of amidase/esterase than S221C/P225A mutant; Although it has no effect on the esterase activity, D60N/N118S/S221C/P225A mutant enhanced its ratio of amidase/esterase by 15 fold, 3.3-fold and 10.3 fold compared to N118S/S221C/P225A mutant, S221C/P225A mutant and subtiligase respectively; Q103R/N118S/S221C/P225A mutant, however, has a 5-fold enhanced in the amidase activity and 55-fold and 1000-fold decrease in the esterase activity and the ratio of esterase/amidase compared to N118S/S221C/P225A.
authors.affiliation: Shanghai Research Center of Biotechnology, Chinese Academy of Sciences. yonghuayang@hotmail.com
authors.forename: Y H
authors.initials: YH
authors.lastname: Yang
authors.forename: L
authors.initials: L
authors.lastname: Jiang
authors.forename: S L
authors.initials: SL
authors.lastname: Yang
authors.forename: Y J
authors.initials: YJ
authors.lastname: Wu
authors.forename: L Q
authors.initials: LQ
authors.lastname: Zhu
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D004950:Esterases / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D013381:Subtilisins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004950:Esterases; D013381:Subtilisins; D000581:Amidohydrolases; C019665:amidase