title: Different inhibition characteristics of intracellular transglutaminase activity by cystamine and cysteamine.
abstract: The treatment of cystamine, a transglutaminase(TGase) inhibitor, has beneficial effects in several diseases including CAG-expansion disorders and cataract. We compared the inhibition characteristics of cystamine with those of cysteamine, a reduced form of cystamine expect-ed to be present inside cells. Cystamine is a more potent inhibitor for TGase than cysteamine with different kinetics pattern in a non-reducing condition. By contrast, under reducing conditions, the inhibitory effect of cystamine was comparable with that of cysteamine. How-ever, cystamine inhibited intracellular TGase activity more strongly than cysteamine despite of cytoplasmic reducing environment, suggest-ing that cystamine itself inhibits in situ TGase activity by forming mixed disulfides.
authors.affiliation: Department of Biochemistry and Molecular Biology/Aging Apoptosis Research Center, Seoul National University College of Medicine, Korea.
authors.forename: Ju-Hong
authors.initials: JH
authors.lastname: Jeon
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Gi-Yong
authors.initials: GY
authors.lastname: Jang
authors.forename: Chai-Wan
authors.initials: CW
authors.lastname: Kim
authors.forename: Dong-Myung
authors.initials: DM
authors.lastname: Shim
authors.forename: Sung-Yup
authors.initials: SY
authors.lastname: Cho
authors.forename: Eui-Ju
authors.initials: EJ
authors.lastname: Yeo
authors.forename: Sang-Chul
authors.initials: SC
authors.lastname: Park
authors.forename: In-Gyu
authors.initials: IG
authors.lastname: Kim
mesh_terms: D045744:Cell Line, Tumor; D003538:Cystamine / Q000494:pharmacology*; D003543:Cysteamine / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D011503:Transglutaminases / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D003543:Cysteamine; D011503:Transglutaminases; D003538:Cystamine