Competitive substrate inhibition of amyloglucosidase from Rhizopus sp. by vanillin and curcumin

Ramaiah, Sivakumar and Giriyapura, R. Vijayakumar and Balaraman, Manohar and Soundar, Divakar (2006) Competitive substrate inhibition of amyloglucosidase from Rhizopus sp. by vanillin and curcumin. Biocatalysis and Biotransformation, 24 (4). pp. 299-305. (Submitted)

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Abstract

Kinetic studies of two glucosylation reactions catalyzed by an amyloglucosidase from Rhizopus sp. leading to the synthesis of vanillin-a/b-D-glucoside from D-glucose and vanillin and curcumin-bis-a-D-glucoside from D-glucose and curcumin were investigated in detail. Initial reaction rates were determined from kinetic runs involving different concentrations of Dglucose and vanillin (5 mM to 0.1 M) or D-glucose and curcumin (5 mM to 0.1 M). Graphical double reciprocal plots showed that the kinetics of the two enzyme catalyzed reactions exhibited Ping-Pong Bi-Bi mechanism where competitive substrate inhibition by vanillin/curcumin led to dead-end amyloglucosidasevanillin/curcumin complexes at higher concentrations of vanillin/curcumin. An attempt to obtain the best fit of this kinetic model through computer simulation yielded in good approximation, the values of four important kinetic parameters, vanillin-a/b-D-glucoside: kcat/35.09/3.2105Mh1/mg, Ki/10.59/1.1 mM, Km D-glucose/60.09/6.2 mM, Km vanillin/50.09/4.8 mM; curcumin-bis-a-D-glucoside:kcat/6.079/0.58 105Mh1/mg, Ki/3.09/0.28 mM, Km D-glucose/10.09/0.9 mM, Km curcumin/4.69/0.5 mM.

Item Type:	Article
Uncontrolled Keywords:	Amyloglucosidasevanillin/curcumin complexes, competitive substrate inhibition, dead-end inhibition by vanillin/ curcumin, hydrogen bonding interactions, phenolic OH and carbonyl groups, Ping-Pong Bi-Bi mechanism
Subjects:	600 Technology > 05 Chemical engineering > 04 Fermentation Technology 500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 16 Enzyme Chemistry
Divisions:	Fermentation Technology and Bioengineering
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	07 Apr 2007
Last Modified:	28 Dec 2011 09:27
URI:	http://ir.cftri.res.in/id/eprint/573

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