Protective effects of D-glucaro 1,4-lactone against oxidative/nitrative modifications of plasma proteins.
OBJECTIVE
The protective effects of D-glucaro 1,4-lactone (1,4-GL) against oxidative/nitrative protein damage (determined by parameters such as levels of protein carbonyl groups and nitrotyrosine residues) to human plasma treated with peroxynitrite (ONOO-) or hydroperoxide (H2O2) were studied in vitro. We also investigated the effects of 1,4-GL on the level of total free thiol groups and low-molecular-weight thiols (glutathione and homocysteine) in plasma treated with ONOO- (0.1 mM).


METHODS
Levels of carbonyl groups and nitrotyrosine residues in human plasma proteins were measured by ELISA and a competition ELISA, respectively. High-performance liquid chromatography (HPLC) was used to analyze free thiols from plasma.


RESULTS
Exposure of plasma to ONOO- (0.1 mM) resulted in an increase of the level of carbonyl groups and nitrotyrosine residues in plasma proteins and in a distinct decrease in total thiols and low-molecular-weight thiols (glutathione and homocysteine) measured by high-performance liquid chromatography. In the presence of 1,4-GL (0.4-6.4 mM), a distinct decrease in carbonyl group formation and tyrosine nitration in plasma proteins and changes in plasma thiols caused by 0.1 mM of peroxynitrite were observed. Moreover, 1,4-GL inhibited plasma protein oxidation induced by H2O2 (2 mM).


CONCLUSIONS
The obtained results indicate that in vitro 1,4-GL has inhibitory effects on ONOO-- or hydroperoxide-mediated oxidative stress in human plasma and changes plasma redox thiol status. The mechanism of the antioxidative action of 1,4-GL present in plasma is not known yet.
Olas
Beata
B
Department of General Biochemistry, University of Lodz, Lodz, Poland. olasb@biol.uni.lodz.pl
Saluk-Juszczak
Joanna
J
Nowak
Pawel
P
Glowacki
Rafal
R
Bald
Edward
E
Wachowicz
Barbara
B
D001798:Blood Proteins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004305:Dose-Response Relationship, Drug; D005937:Glucaric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D005978:Glutathione / Q000097:blood; D006710:Homocysteine / Q000097:blood; D006801:Humans; D006861:Hydrogen Peroxide; D008970:Molecular Weight; D009573:Nitrites / Q000097:blood / Q000378:metabolism; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000032:analysis* / Q000097:blood; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism
D001798:Blood Proteins; D009573:Nitrites; D013438:Sulfhydryl Compounds; D006710:Homocysteine; C002744:3-nitrotyrosine; D014443:Tyrosine; C009194:saccharolactone; D006861:Hydrogen Peroxide; D005978:Glutathione; D005937:Glucaric Acid