title: Mechanism of acid protease catalysis based on the crystal structure of penicillopepsin.
abstract: A proposed mechanism for the catalytic hydrolysis of peptide bonds by acid proteases is similar in many respects to the Zn-carbonyl mechanism previously derived for carboxypeptidase A. In the acid proteases the electrophilic component is the proton shared by Asp-32 and Asp-215; Tyr-75 donates its proton to the amide nitrogen of the scissile bond and an OH- ion from a water molecule bound between the carboxyl group of Asp-32 and the substrate attacks the carbonyl carbon atom.
mesh_terms: D000345:Affinity Labels; D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D010450:Endopeptidases / Q000378:metabolism; D004852:Epoxy Compounds / Q000494:pharmacology; D008958:Models, Molecular; D009596:Nitrophenols / Q000494:pharmacology; D011480:Protease Inhibitors; D011487:Protein Conformation / Q000187:drug effects; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism
chemical_list: D000345:Affinity Labels; D004852:Epoxy Compounds; D009596:Nitrophenols; D011480:Protease Inhibitors; D001224:Aspartic Acid; D014443:Tyrosine; D010450:Endopeptidases