ISSN:
0009-2940
Keywords:
Thiamine pyrophosphate enzymes
;
Thiamine pyrophosphate mechanism
;
Substitutions, site-directed
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The Function of the 4′-Aminopyrimidine Component in the Mechanism of the Catalysis of Thiamine Pyrophosphate Enzymes from Today's ViewBinding mechanism and coenzyme function of thiamine pyrophosphate (TPP) are described with the help of site-directed substitutions at different positions of the coenzyme. In accordance to the earlier suggestions of Langenbeck (see this issue2) it is shown, that besides the thiazolium moiety (C2 atom) also the aminopyrimidine part plays an essential role in the catalytic mechanism of TPP enzymes such as pyruvate decarboxylase, pyruvate dehydrogenase, and transketolase, respectively. A two-center mechanism of TPP is proposed explaining the function of the amino group as an internal proton relay in the catalytic mechanisms of TPP enzymes.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230709
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