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Aminoâacid sequence and glycan structures of cysteine proteases with proline specificity from ginger rhizome Zingiberâofficinale
- Choi, Kyung H., Laursen, Richard A.
- European journal of biochemistry 2000 v.267 no.5 pp. 1516-1526
- N-acetylglucosamine, Zingiber officinale, amino acid sequences, bromelains, cysteine, dissociation, ginger, glycoproteins, glycosylation, histidine, mannose, papain, peptides, polysaccharides, proline, rhizomes, sequence homology, substrate specificity, xylose
- The ginger proteases (GPâI and GPâII), isolated from the ginger rhizome Zingiberâofficinale, have an unusual substrate specificity preference for cleaving peptides with a proline residue at the P2 position. The complete aminoâacid sequence of GPâII, a glycoprotein containing 221 amino acids, and about 98% that of GPâI have been determined. Both proteases, which are 82% similar, have cysteine residues at positions 27 and histidines at position 161, corresponding to the essential cysteineâhistidine diads found in the papain family of cysteine proteases, and six corresponding cysteine residues that form the three invariant disulfide linkages seen in this family of proteins. The sequence homology with other members (papain, bromelain, actinidin, protease omega, etc.) of this family is ââ50%. GPâII has two predicted glycosylation sites at Asn99 and Asn156. Analyisis by electrospray and collisionâinduced dissociation MS showed that both sites were occupied by the glycans (Man)3(Xyl)1(Fuc)1(GlcNAc)2 and (Man)3(Xyl)1(Fuc)1(GlcNAc)3, in a ratio of ââ7â:â1. Both glycans are xylose containing biantennary complex types that share the common core structural unit, Man1â6(Man1â3) (Xyl1â2)Man1â4GlcNAc1â4(Fuc1â3)GlcNAc for the major form, with an additional Nâacetylglucosamine residue being linked, in the minor form, to one of the terminal mannose units of the core structure.