Hydrolases;
Acting on peptide bonds (peptidases);
Aminopeptidases
Reaction(IUBMB)
Release of an N-terminal L-arginine from a protein with only minimal activity against other amino acids. L-Arg-7-amido-4-methylcoumarin is the best artificial substrate.
Comment
The enzyme from the archaeon Pyrococcus horikoshii OT3 is thermostable. In that enzyme Cys100 is the nucleophile responsible for the proteolytic activity, while Tyr120 regulates the catalytic conformation of Cys100 through a hydrogen bond, thereby affecting enzyme activity. The activity with L-Arginine is 90-300 times higher than with other N-terminal amino acids. The enzyme shows low endopeptidase activity.
Experimental and computational studies indicate the mutation of Glu12 to increase the thermostability of oligomeric protease from Pyrococcus horikoshii.
