EPPENDORFER, S and KONIG, S and GOLBIK, R and NEEF, H and LEHLE, K and JAENICKE, R and SCHELLENBERGER, A and HUBNER, G (1993) EFFECTS OF METAL-IONS, THIAMINE DIPHOSPHATE ANALOGS AND SUBUNIT INTERACTIONS ON THE RECONSTITUTION BEHAVIOR OF PYRUVATE DECARBOXYLASE FROM BREWERS-YEAST. BIOLOGICAL CHEMISTRY HOPPE-SEYLER, 374 (12). pp. 1129-1134. ISSN 0177-3593,
Full text not available from this repository.Abstract
The reconstitution of pyruvate decarboxylase starts with reversible binding of thiamine diphosphate and Mg2+-ions to the apoenzyme, followed by a rate-limiting conformational change to the catalytically active holoenzyme. Investigations with diphosphoesters of 4-methyl-5-(2-hydroxyethyl) thiazolium derivatives have shown that the diphosphate residue of thiamine diphosphate is the most important part of the coenzyme responsible for the first reversible binding step. Methylation of the N1'-atom of the pyrimidine ring of thiamine diphosphate or 4'-oxythiamine diphosphate prevents the coenzyme from binding stably to the apoenzyme, so that the methylated coenzyme displays no coenzyme activity. In contrast, thiamine diphosphate analogues with bulky residues on the neighbouring C2'-atom of the pyrimidine ring form active holoenzyme complexes. This result shows the essential role of the N1'-atom of thiamine diphosphate in stable cofactor binding. The cofactor binding rate to the dimeric and tetrameric apoenzymes indicates that the cofactor is located in the contact regions of the subunits in the tetrameric enzyme
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | QUATERNARY STRUCTURE; DEPENDENT ENZYME; PYROPHOSPHATE; SCATTERING; COFACTOR; PYRUVATE DECARBOXYLASE; THIAMINE DIPHOSPHATE |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:42 |
| URI: | https://pred.uni-regensburg.de/id/eprint/53637 |
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