3.4.14.4	C113S	mutation of the cysteine residue	707596	
3.4.14.4	C130S	mutant, only existence of dimeric form	707596	
3.4.14.4	C130S	the mutant exhibits comparable enzymatic activity to the wild type protein	-, 698782	
3.4.14.4	C147A	activity similar to wild type	649555	
3.4.14.4	C176A	25-35% of wild type activity, resistant against p-chloro-mercuri-benzoate and N-ethylmaleimide	649555	
3.4.14.4	C176E	no enzymic activity	649555	
3.4.14.4	C176G	no enzymic activity	649555	
3.4.14.4	C19A	activity similar to wild type	649555	
3.4.14.4	C450S	residues Gly383 and Glu320 form significantly less hydrogen bonds with substrate Arg-Arg-2-naphthylamide than in the wild type enzyme	754693	
3.4.14.4	C509A	activity similar to wild type	649555