Abstract:

Through homologous modeling and docking studies of cysteine protease from Zea mays (zmCP1), W308 was
highly conserved in papain super family (C1 family), near the Asn306 which was the residues of catalytic triad, had π-π
interaction with most of the ligands, and was the key residue for zmCP1. By using Rosseta design program, the mutant
W308C was obtained and expressed in E.coli BL21. The characterization of enzymatic properties indicated that the optimal
temperature and pH were 55 ℃ and 6.0, respectively. T50 of W308C at 70, 80, and 90 ℃ were 75.33, 57.24, and 40.29 min,
respectively, which were 1.21, 1.19 and 1.01 times higher than wild type. Kcat/Km of W308C and wild type was 1.02 and
5.92 L/(μmol·min), respectively, showing an activity level 1.86 times higher than that of wild type.

Key words: cysteine protease, mutant, prokaryotic expression, enzymatic properties