1.
Biosci Biotechnol Biochem
; 61(4): 718-9, 1997 Apr.
Article
in English
| MEDLINE
| ID: mdl-9145532
ABSTRACT
Functional role of Asn219 of aqualysin I, a thermostable serine protease from Thermus aquaticus, was investigated by using site-directed mutagenesis. Replacement of Asn219 with serine increased the catalytic efficiency (kcat/Km) for synthetic peptide substrates about twice as much as that of the wild type, while threonine replacement caused a slight decrease in the efficiency. Such replacements resulted in a significant change of kcat rather than Km, indicating that the side chain in the vicinity of the catalytic residue Ser222 affects the catalytic rate constant.