Different inhibition characteristics of intracellular transglutaminase activity by cystamine and cysteamine.
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.
Jeon
Ju-Hong
JH
Department of Biochemistry and Molecular Biology/Aging Apoptosis Research Center, Seoul National University College of Medicine, Korea.
Lee
Hye-Jin
HJ
Jang
Gi-Yong
GY
Kim
Chai-Wan
CW
Shim
Dong-Myung
DM
Cho
Sung-Yup
SY
Yeo
Eui-Ju
EJ
Park
Sang-Chul
SC
Kim
In-Gyu
IG
D045744:Cell Line, Tumor; D003538:Cystamine / Q000494:pharmacology*; D003543:Cysteamine / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D011503:Transglutaminases / Q000037:antagonists & inhibitors*
D004791:Enzyme Inhibitors; D003543:Cysteamine; D011503:Transglutaminases; D003538:Cystamine