Influence of the Acyl Moiety on the Hydrolysis of Quinuclidinium Esters Catalyzed by Butyrylcholinesterase

Primožič, Ines and Tomić, Srđanka (2011) Influence of the Acyl Moiety on the Hydrolysis of Quinuclidinium Esters Catalyzed by Butyrylcholinesterase. Croatica Chemica Acta, 84 (2). pp. 245-249. ISSN 0011-1643

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Abstract

Eight chiral esters of quinuclidin-3-ol and butyric, acetic, pivalic and benzoic acid were synthesized as well as their racemic and chiral, quaternary N-benzyl derivatives. All racemic and chiral quaternary compounds were studied as substrates and/or inhibitors of horse serum butyrylcholinesterase (BChE). The best substrate for the enzyme was (R)-N-benzyl butyrate. The rates of hydrolysis decreased in order (R)-butyrate >> (R)-acetate (7-fold slower) > (R)-pivalate (8-fold slower) > (R)-benzoate (9-fold slower reaction), while (S)-N-benzyl esters were much poorer substrates (320 (butyrate) - 4360-fold slower (pivalate) than the appropriate (R)-enantiomer). For all (S)-N-benzyl esters excluding (S)-N-benzyl acetate inhibition constants were determined (Ka = 3.3−60 μmol dm−3). The hydrolysis of racemic mixtures of N-benzyl esters proceeded 1.4 (for acetate) − 5.1 (for benzoate) times slower than that of pure (R)-enantiomers of the corresponding concentrations due to the inhibition with (S)-enantiomers. Change of the acyl moiety of the substrate effected both activity and stereoselectivity of the BChE.

Item Type: Article
Keywords: esters of quinuclidin-3-ol, enzymic resolution, butyrylcholinesterase, hydrolysis kinetics, inhibition constants
Date: 2011
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Publisher: Hrvatsko kemijsko društvo
Related URLs:
Depositing User: Branka Maravic
Date Deposited: 09 May 2014 09:49
Last Modified: 09 May 2014 09:49
URI: http://digre.pmf.unizg.hr/id/eprint/1083

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