| 11863445 |
Fang J, Beattie DS: Novel FMN-containing rotenone-insensitive NADH dehydrogenase from Trypanosoma brucei mitochondria: isolation and characterization. Biochemistry. 2002 Mar 5;41(9):3065-72.
A rotenone-insensitive NADH dehydrogenase has been isolated from the mitochondria of the procyclic form of African parasite, Trypanosoma brucei. The active form of the purified enzyme appears to be a dimer consisting of two 33-kDa subunits with noncovalently bound FMN as a cofactor. Hypotonic treatment of intact mitochondria revealed that the NADH dehydrogenase is located in the inner membrane/matrix fraction facing the matrix. The treatment of mitochondria with increasing concentrations of digitonin suggested that the NADH dehydrogenase is loosely bound to the inner mitochondrial membrane. The NADH:ubiquinone reductase activity is insensitive to rotenone, flavone, or dicumarol; however, it was inhibited by diphenyl iodonium in a time- and concentration-dependent manner. Maximum inhibition by diphenyl iodonium required preincubation with NADH to reduce the flavin. More complete inhibition was obtained with the more hydrophobic electron acceptors, such as Q (1) or Q (2), as compared to the more hydrophilic ones, such as Q (0) or dichloroindophenol. Kinetic analysis of the enzyme indicated that the enzyme followed a ping-pong mechanism. The enzyme conducts a one-electron transfer and can reduce molecular oxygen forming superoxide radical. |
14(0,0,2,4) |