Avtor/Urednik		Buttle, DJ; Ritonja, A; Pearl, LH; Turk, V; Barrett, AJ
Naslov		Selective cleavage of glycyl bonds by papaya proteinase IV
Tip		članek
Vir		FEBS Lett
Vol. in št.		Letnik 260, št. 2
Leto izdaje		1990
Obseg		str. 195-7
Jezik		eng
Abstrakt		The specificity of papaya proteinase IV (PPIV) has been examined with small substrates and a protein. With both classes of substrate, the enzyme shows a marked selectivity for cleaving glycyl bonds. Boc-Ala-Ala-Gly-NHPhNO2 is a convenient substrate for routine assays that discriminate well against chymopapain, the most common contaminant of PPIV. Sixteen cleavage points in beta-trypsin were identified, of which 13 are glycyl bonds. Tentative suggestions are made as to the reasons for lack of cleavage of some other glycyl bonds. The structure of PPIV has been modelled on that of papain, and we suggest that the replacement of the highly conserved residues Gly-65 and Gly-23 by arginine and glutamic acid, respectively, can account for the specificity of PPIV.
Deskriptorji		FRUIT GLYCINE PEPTIDE HYDROLASES TRYPSIN AMINO ACID SEQUENCE BINDING SITES HYDROLYSIS KINETICS MODELS, MOLECULAR MOLECULAR SEQUENCE DATA SUBSTRATE SPECIFICITY TRYPSIN