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Elucidation of the Enantioselective Cyclohexane‐1,2‐dione Hydrolase Catalyzed Formation of ( S )‐Acetoin
Author(s) -
Loschonsky Sabrina,
Waltzer Simon,
Brecht Volker,
Müller Michael
Publication year - 2014
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300904
Subject(s) - acetoin , chemistry , acetaldehyde , enantioselective synthesis , thiamine , stereochemistry , enzyme , cyclohexane , catalysis , combinatorial chemistry , biochemistry , organic chemistry , fermentation , ethanol
Thiamine diphosphate (ThDP) dependent enzymes catalyze the formation of acetoin (3‐hydroxybutan‐2‐one) through one of three different pathways: homocoupling of pyruvate, homocoupling of acetaldehyde, or cross‐coupling of acetaldehyde (as acceptor) and pyruvate (as donor). The enantioselectivity of the resulting acetoin is highly dependent on the particular enzyme. We established that ThDP‐dependent cyclohexane‐1,2‐dione hydrolase (CDH) is able to form ( S )‐acetoin with particularly high enantioselectivity (up to 95 % ee ) by all three pathways. Mechanistic studies utilizing 13 C‐labeled substrates revealed an unprecedented non‐acetolactate pathway for the homocoupling of pyruvate, which explains the high enantioselectivity in the CDH‐catalyzed formation of ( S )‐acetoin.