Premium
Protective action of CLA against oxidative inactivation of paraoxonase 1, an antioxidant enzyme
Author(s) -
Su NguyenDuy,
Liu XiWen,
Kim Mee Ree,
Jeong TaeSook,
Sok DaiEun
Publication year - 2003
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-003-1106-9
Subject(s) - chemistry , antioxidant , paraoxonase , linoleic acid , cysteine , oxidative phosphorylation , biochemistry , pon1 , enzyme , fatty acid , genotype , gene
The effect of CLA on paraoxonase 1 (PON1), one of the antioxidant proteins associated with HDL, was investigated for its protective action against oxidative inactivation as well as its stabilization activity. When cis ‐9 ( c 9), trans ‐11 ( t 11)‐CLA and t 10, c 12‐CLA were examined for their protective activity against ascorbate/Cu 2− ‐induced inactivation of PON1 in the presence of Ca 2+ , two CLA isomers exhibited a remarkable protection ( E max , 71–74%) in a concentration‐dependent manner (50% effective concentration, 3–4 μM), characterized by a saturation pattern. Such a protective action was also reproduced with oleic acid, but not linoleic acid. Rather, linoleic acid antagonized the protective action of CLA isomers in a noncompetitive fashion. Additionally, the two CLA isomers also protected PON1 from oxidative inactivation by H 2 O 2 or cumene hydroperoxide. The concentration‐dependent protective action of CLA against various oxidative inactivation systems suggests that the protective action of CLA isomers may be mediated through their selective binding to a specific binding site in a PON1 molecule. Separately, the inactivation of PON1 by p ‐hydroxymercuribenzoate (PHMB), a modifier of the cysteine residue, was also prevented by CLA isomers, suggesting the possible existence of the cysteine residue in the binding site of CLA. The c 9, t 11‐CLA isomer seems to be somewhat more effective than t 10, c 12‐CLA in protecting against the inactivation of PON1 by either peroxides or PHMB, in contrast to the similar efficacy of these two CLA isomers in preventing ascorbate/Cu 2+ ‐induced inactivation of PON1. Separately, CLA isomers successfully stabilized PON1, but not linoleic acid. These data suggest that the two CLA isomers may play a beneficial role in protecting PON1 from oxidative inactivation as well as in its stabilization.