peptidyl chloromethyl ketones , largely derived from arginine , inactivate cathepsin b ( beef spleen ) at rates that vary 300 fold according to sequence , but the residue in the p1 position is not responsible for this variation since homoarginine or nitroarginine in this position provide inhibitors as good or better than those containing arginine .
C0019877
homoarginine
C0003765
arginine