Kinetic mechanism of pyruvate decarboxylase Evidence for a specific protonation of the enzymic intermediate
- 9 March 1992
- journal article
- Published by Wiley in FEBS Letters
- Vol. 299 (2) , 163-165
- https://doi.org/10.1016/0014-5793(92)80238-c
Abstract
Decarboxylation of pyruvate by pyruvate decarboxylase (EC 4.1.1.1) was performed in a reaction mixture containing 50% deuterium. The isolated product, acetaldehyde, was investigated directly by 1H NMR and by mass spectrometry after conversion to the 2,4‐dinitrophenyl hydrazone. The protium content of 56% at acetaldehyde Cl demonstrate a specific protonation of the corresponding intermediate by the enzyme. Proton inventory studies and enzyme modification indicate the 4′ amino group of the coenzyme, thiamine pyrophosphate, in an immonium structure being a possible proton donor. A ‘partially concerted’ mechanism is suggested for the reaction steps following the decarboxylation.Keywords
This publication has 10 references indexed in Scilit:
- Crystal structure of thiamine thiazolone: a possible transition-state analog with an intramolecular N-H.cntdot..cntdot..cntdot.O hydrogen bond in the V formJournal of the American Chemical Society, 1986
- THE AMINO GROUP AND STERIC FACTORS IN THIAMIN CATALYSISAnnals of the New York Academy of Sciences, 1982
- [29] Solvent isotope effects on enzyme systemsPublished by Elsevier ,1982
- N1'-Methylthiaminium diiodide. Model study on the effect of a coenzyme bound positive charge on reaction mechanisms requiring thiamin pyrophosphateJournal of the American Chemical Society, 1978
- Solvent Hydrogen Isotope EffectsPublished by Springer Nature ,1978
- Kinetischer 15N‐Isotopieeffekt als direkter Beweis für die unmittelbare Beteiligung der Aminogruppe von Thiaminpyrophosphat an der enzymatischen Decarboxylierung von α‐Ketosäuren durch Hefe‐PyruvatdecarboxylaseZeitschrift für Chemie, 1975
- Studies on the Properties of (—)‐2‐α‐Hydroxyethyl‐Thiamine Pyrophosphate (“Active Acetaldehyde”)European Journal of Biochemistry, 1967
- Zur Theorie der Cocarboxylasewirkung, II. Ableitung und Begründung eines Zweizentrenmechanismus der Thiaminpyrophosphatwirkung aus Modellversuchen und enzymatischen MessungenHoppe-Seyler´s Zeitschrift Für Physiologische Chemie, 1966
- Nachweis und charakterisierung von α-lactyl-thiaminpyrophosphat (“aktives pyruvat”) und α-hydroxyäthyl-thiaminpyrophosphat (“aktiver acetaldehyd”) als zwischenprodukte der decarboxylierung von pyruvat mit pyruvatdecarboxylase aus bierhefeBiochimica et Biophysica Acta, 1961
- Studies on Model Systems for Thiamine Action. Synthesis of Reactive Intermediates, and Evidence on the Function of the Pyrimidine Ring1Journal of the American Chemical Society, 1959