G. Pal et al., ALTERATION OF THE SPECIFICITY OF ECOTIN, AN ESCHERICHIA-COLI SERINE PROTEINASE-INHIBITOR, BY SITE-DIRECTED MUTAGENESIS, FEBS letters, 342(1), 1994, pp. 57-60
The gene of ecotin, an E. call proteinase inhibitor, was cloned, and b
y site-directed mutagenesis the active site residue of the protein, Me
t(84), was mutated to Lys, Arg and Leu. The recombinant wild-type and
mutant inhibitors were overexpressed in E. coli, purified to homogenei
ty and their inhibitory effects on trypsin, chymotrypsin and elastase
were compared. Of these serine proteinases trypsin is the most strongl
y inhibited by wild type ecotin and its mutants. According to our resu
lts the character of residue 84 of ecotin significantly but not dramat
ically modifies the specificity of the inhibitor.