Premium
Reaction mechanisms of thiamin diphosphate enzymes: defining states of ionization and tautomerization of the cofactor at individual steps
Author(s) -
Nemeria Natalia S.,
Chakraborty Sumit,
Balakrishnan Anand,
Jordan Frank
Publication year - 2009
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2009.06964.x
Subject(s) - tautomer , cofactor , chemistry , intramolecular force , ring (chemistry) , electrophile , ionization , proton , transketolase , catalysis , covalent bond , enzyme , computational chemistry , photochemistry , stereochemistry , combinatorial chemistry , biochemistry , organic chemistry , ion , physics , quantum mechanics
We summarize the currently available information regarding the state of ionization and tautomerization of the 4′‐aminopyrimidine ring of the thiamine diphosphate on enzymes requiring this coenzyme. This coenzyme forms a series of covalent intermediates with its substrates as an electrophilic catalyst, and the coenzyme itself also carries out intramolecular proton transfers, which is virtually unprecedented in coenzyme chemistry. An understanding of the state of ionization and tautomerization of the 4′‐aminopyrimidine ring in each of these intermediates provides important details about proton movements during catalysis. CD spectroscopy, both steady‐state and time‐resolved, has proved crucial for obtaining this information because no other experimental method has provided such atomic detail so far.