A cytosolic flavin-containing enzyme catalyzing reduction of cytochrome c in Trypanosoma cruzi: kinetic studies with cytochrome c as substrate.
The kinetic mechanism of cytochrome c reduction by a Trypanosoma cruzi cytosolic flavoenzyme was investigated by initial velocity determinations, by product inhibition patterns, and by the characteristics of inhibition by analogs. The data suggest a two-site ping-pong mechanism in which NADPH reduces the flavin, which is then reoxidized in two one-electron steps by reaction with two molecules of cytochrome c. The two-site nature of the mechanism is probably related to the dimeric nature of the enzyme, and the binding sites of cytochrome c and NADPH are probably on opposite sites of the FAD.
Kuwahara
T
T
White
R A
RA
Agosin
M
M
D000249:Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D003574:Cytochrome c Group / Q000378:metabolism*; D005420:Flavoproteins / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D009249:NADP / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000201:enzymology*
D003574:Cytochrome c Group; D005420:Flavoproteins; D046911:Macromolecular Substances; D000249:Adenosine Monophosphate; D009249:NADP; D009251:NADPH-Ferrihemoprotein Reductase