title: First report on a potato I family chymotrypsin inhibitor from the seeds of a Cucurbitaceous plant, Momordica cochinchinensis.
abstract: A 7514-Da chymotrypsin inhibitor was isolated from the seed extract of Momordica cochinchinensis (Family Cucurbitaceae) by chromatography on chymotrypsin-Sepharose 4B and subsequently by C18 reversed-phase HPLC. This inhibitor, named MCoCl, possessed remarkable thermostability and was stable from pH 2 to 12. MCoCl also inhibited subtilisin, but had at least 50-fold lower inhibitory activity towards trypsin and elastase. Amino acid sequencing of a peptide fragment of MCoCl revealed a sequence of 23 amino acids. Comparison of this sequence and the molecular mass with those of other protease inhibitors suggests that MCoCl belongs to the potato I inhibitor family.
authors.affiliation: Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
authors.forename: Alex Y K
authors.initials: AY
authors.lastname: Tsoi
authors.forename: Ricardo C H
authors.initials: RC
authors.lastname: Wong
authors.forename: Tzi-Bun
authors.initials: TB
authors.lastname: Ng
authors.forename: Wing-Ping
authors.initials: WP
authors.lastname: Fong
mesh_terms: D000595:Amino Acid Sequence; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D029775:Momordica / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D010446:Peptide Fragments / Q000235:genetics; D012639:Seeds / Q000201:enzymology*; D016415:Sequence Alignment; D015842:Serine Proteinase Inhibitors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D011198:Solanum tuberosum / Q000201:enzymology; D013381:Subtilisins / Q000037:antagonists & inhibitors; D014357:Trypsin / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D015842:Serine Proteinase Inhibitors; D013381:Subtilisins; D002918:Chymotrypsin; D010196:Pancreatic Elastase; D014357:Trypsin