Linked Life Data

9030530

Source:http://linkedlifedata.com/resource/pubmed/id/9030530

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1997-4-3
pubmed:abstractText
Dermal 7alpha- and 7beta-hydroperoxycholest-5-en-3beta-ols (cholesterol 7alpha- and 7beta-hydroperoxides), regarded as good aging markers in the rat (Ozawa, N., Yamazaki, S., Chiba, K., Aoyama, H., Tomisawa, H., Tateishi, M., and Watabe, T. (1991) Biochem. Biophys. Res. Commun. 178, 242-247), were reduced in the presence of glutathione (GSH) with concomitant formation of GSSG by cytosol from rat liver in which no detectable level of the hydroperoxides had been demonstrated to occur. The GSH peroxidase (GSH Px) activity toward the toxic steroid hydroperoxides was exerted to almost the same extent by both Alpha-class GSH S-transferases (GSTs), Ya-Ya and Ya-Yc, and by selenium-containing GSH Px (Se-GSH Px) in rat liver cytosol. None of three Mu-class GSTs, Yb1-Yb1, Yb1-Yb2, and Yb2-Yb2, and a Theta-class GST, Yrs-Yrs, from rat liver and a Pi-class GST, Yp-Yp, from rat kidney showed any appreciable GSH Px activity toward the hydroperoxides. The subunit Ya-bearing GSTs and Se-GSH Px purified from rat liver cytosol showed marked differences in apparent specific activity toward the cholesterol hydroperoxides (GSTs Ya-Ya > Ya-Yc >> Se-GSH Px). However, a kinetic study indicated that Se-GSH Px had a higher affinity for steroid hydroperoxides than did the GSTs, so that Se-GSH Px could catalyze the reduction of lower concentrations of cholesterol 7-hydroperoxides with approximately equal Vmax/Km values to those by the GSTs. Rat skin had no GST bearing the subunit Ya but contained only a very low concentration of Se-GSH Px, possibly resulting in the accumulation of cholesterol 7-hydroperoxides in the skin but not in the liver. From rat skin cytosol, GSTs Yc-Yc, Yb1-Yb1, Yb1-Yb2, Yb2-Yb2, and Yp-Yp were isolated, purified to homogeneity, and identified with the corresponding GSTs from liver and kidney. The GSTs accounted for 0.23% of total skin cytosolic protein, and the most abundant isoform of skin GSTs was Yb2-Yb2, followed by Yc-Yc, Yp-Yp, Yb1-Yb1, and Yb1-Yb2 in decreasing order.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4763-9
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Subunit Ya-specific glutathione peroxidase activity toward cholesterol 7-hydroperoxides of glutathione S-transferases in cytosols from rat liver and skin.
pubmed:affiliation
Department of Drug Metabolism and Molecular Toxicology, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji-shi, Tokyo 192-03, Japan.
pubmed:publicationType
Journal Article