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CONVERSION OF LINOLEIC ACID HYDROPEROXIDE BY FRENCH BEAN HYDROPEROXIDE ISOMERASE
Author(s) -
KERMASHA S.,
VOORT F.R.,
METCHE M.
Publication year - 1986
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1986.tb00106.x
Subject(s) - linoleic acid , chemistry , silicic acid , chromatography , hexanal , isomerase , enzyme , organic chemistry , fatty acid
Hydroperoxide isomerase (HPI) was extracted from the cotolydon portion of sprouted French bean see & afer five days of incubation and partially purified by ammonium sulphate fractionation and ultracentrifugation. Linoleic acid hydroperoxides (LAHPO) were produced using commercial soybean lipoxygenase and purified using a silicic acid column and identijed by HPLC. The characterized LAHPOs were used as substrates for the French bean HPI. The purified French bean extract showed a three foid increase in activity over the crude preparation and a pH optimum of 7.2. Iheprimary end‐products of the enzyme reaction were separated into ketol and carbonyl compounds and then further purified by preparative TLC. Subsequent GC‐MS analysis of the ketolfraction indicated that HPI converted the 13‐hydroperoxyoctadec‐9, I1 dienoic acid primarily into 10,13‐dihydroqoctadec‐11 ‐enoicacid 0‐ketol) and to a lesser extent into 12,13‐dihydronyoctadec‐9‐enoic acid (a‐ketol). Trace amounts of 9,12‐dihydroxyoctadec‐lO‐enoic acid resulting from the isomerization of 9‐hydroperoxyoctadec‐10.12‐dienoic acid were also found. Hexanal was revealed to be the principal carbonyl compound resulting from the decomposition of I3‐hydroperonyoctadec‐9,Il‐dienoic acid, suggesting that a lyase was also present in the French bean extract.