Mechanistic studies on thiamin formation and degradation: Thiaminase I and thiamin phosphate synthase

T. P. Begley, N. Campobasso, C. Costello, R. Nicewonger, N. Kelleher, F. McLatferty, I. Chiu, S. Ealick, Y. Z. Hang, J. Reddick, C. Kinesjand

Research output: Contribution to journalArticlepeer-review

Abstract

Mechanistic studies on two enzymes catalyzing substitution reactions on the pyrimidirie moiety of thiamin will be described. Thiamin phosphate synthase catalyzes the displacement of the pyrophosphate of 2-methyl-4-amino5-hydroxymethylpynmidine pyrophosphate by 4 methyl-5-hydroxyethylthiazole phosphate. A mechanism for this reaction which is consistent with substituent effects and with the X ray crystal structure of the enzyme/thiamin phosphate/pyrophosphate ternary complex will be described. Thiaminase I catalyzes the displacement of the thiazole moiety of thiamin by a variety of nucleophiles. A mechanistic proposal for this enzyme will be described. This proposal is consistent with the stereochemistry of the reaction, with the inactivation of the enzyme with 2-methyl-4-amino-6 chloropyrimidine and with the X ray crystal structure of the mechanism based inactivated enzyme.

Original languageEnglish (US)
JournalFASEB Journal
Volume12
Issue number8
StatePublished - Dec 1 1998

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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