title: Remarkable activity enhancement of thermolysin mutants.
abstract: Most attempts to modify the properties of enzymes by amino acid substitution around the active sites have resulted in suppression of the biological activity, suggesting that the structure of natural enzymes should be almost optimized evolutionally to show the highest activity. In contrast, we found an interesting site of a well-known metalloendopeptidase, thermolysin (EC.3.4.24.4), where almost all the amino acid replacement causes a remarkable increase in the hydrolytic activity. Negative correlation between the activity and the thermal stability was observed. The flexibility around the substrate binding site is suggested to be a key to the correlation. Nature may have selected the amino acid at this site, which suppresses the flexibility of the molecule, to get the highest thermal stability at the expense of the activity.
authors.affiliation: Sagami Chemical Research Center, Kanagawa, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kidokoro
authors.forename: Y
authors.initials: Y
authors.lastname: Miki
authors.forename: K
authors.initials: K
authors.lastname: Endo
authors.forename: A
authors.initials: A
authors.lastname: Wada
authors.forename: H
authors.initials: H
authors.lastname: Nagao
authors.forename: T
authors.initials: T
authors.lastname: Miyake
authors.forename: A
authors.initials: A
authors.lastname: Aoyama
authors.forename: T
authors.initials: T
authors.lastname: Yoneya
authors.forename: K
authors.initials: K
authors.lastname: Kai
authors.forename: S
authors.initials: S
authors.lastname: Ooe
mesh_terms: D004789:Enzyme Activation / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D013820:Thermolysin / Q000235:genetics* / Q000378:metabolism
chemical_list: D013820:Thermolysin