TWO-SITE PROPERTY OF THENOYLTRIFLUOROACETONE INHIBITING SUCCINATE-UBIQUINONE REDUCTASE  

作　　者：徐建兴 TSOO E.KING 

机构地区：[1]Institute of Biophysics, Academia Sinica, Beijing 100080, PRC [2]Institute for Structural and Functional Studies, University City Science Center and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia PA 19104

出　　处：《Science China Chemistry》1992年第2期162-168,共7页中国科学（化学英文版）

基　　金：This work was co-supported by Grants NIH GM-16767 of USA and the National Natural Science Foundation of China

摘　　要：It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone (TTFA) has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The high affinity site (inhibited at the concentration of thenoyltrifluoroacetone less than 20 μmol/L) shows noncompetitive with substrate Q_2, while the low affinity site (inhibited at the concentration of TTFA over 20 μmol/L) shows competitive. It is suggested that both the reducing steps of Q→QH and QH→QH_2 are inhibited by thenoyltrifluoroacetone.It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone （TTFA） has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The high affinity site （inhibited at the concentration of thenoyltrifluoroacetone less than 20 μmol/L） shows noncompetitive with substrate Q₂, while the low affinity site （inhibited at the concentration of TTFA over 20 μmol/L） shows competitive. It is suggested that both the reducing steps of Q→QH and QH→QH₂ are inhibited by thenoyltrifluoroacetone.

关 键 词：succinate-ubiquinone REDUCTASE inhibition TTFA. 

分 类 号：O6[理学—化学]