title: Primary structure and disulfide bridge location of arrowhead double-headed proteinase inhibitors.
abstract: Two arrowhead proteinase inhibitors (inhibitors A and B) were characterized and their primary structures were determined. Both inhibitors A and B are double-headed and multifunctional protease inhibitors. Inhibitor A inhibits an equimolar amount of trypsin and chymotrypsin simultaneously and weakly inhibits kallikrein. Inhibitor B inhibits two molecules of trypsin simultaneously and inhibits kallikrein more strongly than does inhibitor A. The amino acid sequences of inhibitors A and B were determined by sequencing the reduced and S-carboxamidomethylated proteins and their peptides produced by cyanogen bromide or proteolytic lysylendopeptidase or Staphylococcus aureus V8 protease cleavage. Inhibitors A and B consist of 150 amino acid residues with three disulfide bonds (Cys 43-Cys 89, Cys 110-Cys 119, and Cys 112-Cys 115) and share 90% sequence identity, with 13 different residues. Since the primary structures are totally different from those of all other serine protease inhibitors so far known, these inhibitors might be classified into a new protease inhibitor family.
authors.affiliation: Department of Biochemistry, Nanjing University, People's Republic of China.
authors.forename: H L
authors.initials: HL
authors.lastname: Yang
authors.forename: R S
authors.initials: RS
authors.lastname: Luo
authors.forename: L X
authors.initials: LX
authors.lastname: Wang
authors.forename: D X
authors.initials: DX
authors.lastname: Zhu
authors.forename: C W
authors.initials: CW
authors.lastname: Chi
mesh_terms: D000595:Amino Acid Sequence; D004220:Disulfides / Q000737:chemistry*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry*; D011480:Protease Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism
chemical_list: D004220:Disulfides; D010940:Plant Proteins; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; C036813:lysyl endopeptidase