ENTRY       EC 3.4.23.4
NAME        Chymosin
            Rennin
CLASS       Hydrolases
            Acting on peptide bonds (peptidases)
            Aspartic endopeptidases
REACTION    Preferential cleavage: hydrophobic, preferably aromatic, residues
            in P1 and P1' positions.  Cleaves Phe1+Val, Gln4+His, Glu13+Ala,
            Ala14+Leu, Leu15+Tyr, Tyr16+Leu, Gly23+Phe, Phe24+Phe and
            Phe25+Tyr bonds in the B chain of insulin.
            Clots milk by cleavage of a single Ser-Phe105+Met-Ala bond in
            kappa-chain of casein
REACTION    Cleaves a single bond in casein k
SUBSTRATE   Protein
            Peptide
            Casein K
            H2O
PRODUCT     Protein
            Peptide
COMMENT     Neonatal gastric proteinase with high milk clotting and weak
            general proteolytic activity. Found among mammals with pastnatal
            uptake of imminoglobulins. Formed from prochymosin by a limited
            proteolysis that removes a propart of 42 amino acid residues from
            the N-terminal of the zymogen.
MOTIF       PS: PS00141  [LIVMFGAC]-[LIVMTADN]-[LIVFSA]-D-[ST]-G-[STAV]-
                         [STAPDENQ]-x-[LIVMFSTNC]-x-[LIVMFGTA]
STRUCTURES  PDB: 4CMS  3CMS  1CZI  1CMS  
DBLINKS     University of Geneva ENZYME DATA BANK: 3.4.23.4
            WIT (What Is There) Metabolic Reconstruction: 3.4.23.4
            SCOP (Structural Classificaion of Proteins): 3.4.23.4
///