title: Electrophoretic analysis of the "cross-class" interaction between novel inhibitory serpin, squamous cell carcinoma antigen-1 and cysteine proteinases.
abstract: We investigated the "cross-class" interaction between cysteine proteinases and a novel inhibitory serpin, recombinant squamous cell carcinoma (rSCC) antigen-1, which inhibits a serine proteinase, chymotrypsin. rSCC antigen-1 inhibited the cysteine proteinases, papain, papaya proteinase IV and cathepsin L. Interestingly, although rSCC antigen-1 formed sodium dodecyl sulfate (SDS)- and heat-stable complexes with chymotrypsin, rSCC antigen-1 gave the 40 kDa fragment and small molecular mass peptide by incubation with papain without forming an SDS- and heat-stable complex. The cleavage was observed between the Gly353-Ser354 bond, indicating that rSCC antigen-1 interacts with cysteine proteinases not at the predicted reactive site P1-P1' portion (Ser354-Ser355), but at the Gly353-Ser354 of the P2-P1 portion. These findings promote understanding of the "suicide inhibition" mechanism of SCC antigen-1 against cysteine proteinases.
authors.affiliation: Department of Obstetrics and Gynecology, Yamaguchi University School of Medicine, Ube, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nawata
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: F
authors.initials: F
authors.lastname: Numa
authors.forename: Y
authors.initials: Y
authors.lastname: Suminami
authors.forename: N
authors.initials: N
authors.lastname: Tsunaga
authors.forename: H
authors.initials: H
authors.lastname: Kakegawa
authors.forename: N
authors.initials: N
authors.lastname: Katunuma
authors.forename: H
authors.initials: H
authors.lastname: Kato
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000494:pharmacology*; D001665:Binding Sites; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D008247:Lysosomes / Q000201:enzymology; D010206:Papain / Q000037:antagonists & inhibitors; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology; D015843:Serpins / Q000235:genetics / Q000494:pharmacology*
chemical_list: D000951:Antigens, Neoplasm; D015853:Cysteine Proteinase Inhibitors; D011993:Recombinant Fusion Proteins; D015843:Serpins; C051072:squamous cell carcinoma-related antigen; D002918:Chymotrypsin; D003546:Cysteine Endopeptidases; D010206:Papain; C050874:glycyl endopeptidase