Interaction of dihydroxyethylthiamine pyrophosphate with transketolase.
Deprotonated form of dihydroxyethylthiamine pyrophosphate (DHETPP) is an intermediate product of the transketolase reaction. We have shown that when added to the reaction medium DHETPP can act as a substrate of the holoenzyme. The rate of the enzymatic reaction is quite close to that observed with ordinary substrates of transketolase. This fact suggests that the interaction of DHETPP with the holotransketolase and its deprotonation are not rate-limiting steps of the transketolase reaction.
Usmanov
R A
RA
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
Sidorova
N N
NN
Kochetov
G A
GA
D001051:Apoenzymes / Q000737:chemistry / Q000378:metabolism; D002942:Circular Dichroism; D003067:Coenzymes / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008956:Models, Chemical; D013379:Substrate Specificity; D013835:Thiamine Pyrophosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D014174:Transketolase / Q000737:chemistry / Q000378:metabolism*
D001051:Apoenzymes; D003067:Coenzymes; C093420:dihydroxyethylthiamine pyrophosphate; D014174:Transketolase; D013835:Thiamine Pyrophosphate