31P NMR investigations on free and enzyme bound thiamine pyrophosphate |
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| Authors: | S Flatau G Fischer E Kleinpeter A Schellenberger |
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| Institution: | Dept of Biochemistry, University of Halle, GDR. |
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| Abstract: | Pyruvate decarboxylase (PDC) contains thiamine pyrophosphate (TPP) and Mg2+ as cofactors. 31P NMR studies with PDC in the presence of added Mn2+ reveal the pyrophosphate moiety of TPP to be a nonaccessible area for the external Mn2+ and thus proving the Mg-P-complex (taking part in the binding of the coenzyme to the protein) to be a nonaccessible area for the medium. Glyoxylic acid, acting as an inhibitor of PDC by forming a noncleavable bond with the catalytic center of TPP causes a steric immobilization of the coenzyme indicated by a line broadening of the pyrophosphate moiety. |
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