* To whom correspondence should be addressed.
Received December 14, 2009; Revision received March 22, 2010
The effect of hexacyanoferrate(III) on the catalytic activity of transketolase has been studied. This oxidant inactivates only one of two active sites of the enzyme, the one with a higher affinity to the coenzyme (thiamine diphosphate). The second active site does not lose its catalytic activity. These observations indicate that the active sites of holotransketolase, being indiscernible by data of X-ray analysis, exhibit functional nonequivalence.
KEY WORDS: transketolase, nonequivalence of active sites, inhibitors, hexacyanoferrate