Leu and Val12Glu in B chain of insulin
Reaction: Hydrolysis of proteins with broad specificity similar to that of pepsin A, preferring hydrophobic residues at P1 and P1'. Clots milk and activates trypsinogen. Does not cleave Gln4-His, but does cleave His10Leu and Val12Glu in B chain of insulin
Other names: Rhizopus aspartic proteinase; neurase; Rhizopus acid protease; Rhizopus acid proteinase
Comments: From the zygomycete fungus Rhizopus chinensis. A similar endopeptidase is found in R. niveus [2]. In peptidase family A1 (pepsin A family). Formerly EC 3.4.23.9, and included in EC 3.4.23.6
Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, PDB, CAS registry number: 9074-09-3
References:
1. Tsuru, D., Hattori, A., Tsuji, H., Yamamoto, T. and Fukumoto, J. Studies on mold proteases. Part II. Substrate specificity of acid protease of Rhizopus chinensis. Agric. Biol. Chem. 33 (1969) 1419-1426
2. Kurono, Y., Chidimatsu, M., Horikoshi, K. and Ikeda, Y. Isolation of a protease from a Rhizopus product. Agric. Biol. Chem. 35 (1971) 1668-1675
3. Ohtsuru, M., Tang, J. and Delaney, R. Purification and characterization of rhizopuspesin isozymes from a liquid culture of Rhizopus chinensis. Int. J. Biochem. 14 (1982) 925-932. [PMID: 6751894]
4. Suguna, K., Padlan, E.A., Smith, C.W., Carlson, W.D. and Davies, D.R. Binding of a reduced peptide inhibitor to the aspartic proteinase from Rhizopus chinensis: implications for a mechanism of action. Proc. Natl. Acad. Sci. USA 84 (1987) 7009-7013. [PMID: 3313384]