3.4.22.66	C104S	site-directed mutagenesis, the mutant is affected in its catalytic activity of proteolytic processing	718084	
3.4.22.66	C116S	site-directed mutagenesis, the mutant is affected in its catalytic activity of proteolytic processing	718084	
3.4.22.66	C122S	site-directed mutagenesis, the mutant is affected in its catalytic activity of proteolytic processing	718084	
3.4.22.66	C139A	cysteine residue responsible for hydrolysis	671000	
3.4.22.66	C139S	site-directed mutagenesis, the mutant is affected in its catalytic activity of proteolytic processing	718084	
3.4.22.66	E54A	Glu at the active centre	670097	
3.4.22.66	E54L	the E54L mutant protease is a substrate-specificity mutant and requires large hydrophobic amino acid residues at both P4 and P2 positions of the substrate, it cleaves the sequence 133LSFE/AP between the 3B and 3C regions of norovirus polyprotein, but does not cleaves the sequence 198ATSE/GK between the 3A and 3B	708950	
3.4.22.66	additional information	acidic amino acid (Glu or Asp), as well as the His and Cys in the putative catalytic triad, cannot be replaced by Ala for normal processing activity of the ORF1 polyprotein in vitro. Similarly, normal activity is not retained if the nucleophile Cys is replaced with Ser	718084