Open AccessPurification and Kinetic Properties of Chalcone‐Flavanone Isomerase from Soya Bean
Author(s) -
BOLAND Michael J.,
WONG Edmon
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb09814.x
Subject(s) - flavanone , chemistry , chalcone isomerase , chalcone , isoliquiritigenin , flavonoid , isomerase , flavonoid biosynthesis , isomerization , catalysis , enzyme , turnover number , stereochemistry , biochemistry , chalcone synthase , biosynthesis , transcriptome , gene expression , gene , antioxidant
The chalcone‐flavanone isomerase from soya bean seed has been purified 8300‐fold. A molecular weight of 15600 ± 1000 has been determined for the enzyme. Effects of iodoacetamide and sodium tetrathionate on the enzyme, and pH dependence of the catalytic step, indicate that a sulphydryl group is not involved in the reaction mechanism and the catalytic group is probably an imidazole side chain in the basic form. The kinetics of the isomerisation of isoliquiritigenin to liquiritigenin have been examined and show that at pH 7.6 the reaction is reversible with an equilibrium constant of 37 in favour of flavanone. A number of flavonoid compounds competitively inhibit the reaction, suggesting a possible regulatory role for this enzyme in flavonoid biosynthesis.