Purification and characterization of glutathione peroxidase from human blood platelets. Age-related changes in the enzyme.
Platelet glutathione peroxidase (GPx) is known to play a pivotal role in controlling the level of lipid hydroperoxides, especially those resulting from the 12-lipoxygenase activity. GPx was purified from the cell cytosol by more than 700-fold using an exchange chromatography, FPLP, gel filtration and covalent fixation. Isoelectric focusing revealed a peak activity at pH 5.1. The molecular mass of the enzyme was found between 90 and 100 kDa by gel filtration, and was approximating at 23 kDa by SDS-PAGE. A polyclonal antibody raised against commercial bovine erythrocyte GPx recognized the human platelet enzyme. It is concluded that human platelet GPx is likely a homotetramer of 92 kDa as described for most other sources. We have also found that the decreased platelet GPx activity observed in platelets from elderly people is associated with a lower content of the immunoreactive enzyme.
Rey
C
C
INSERM U.352, INSA-Lyon, Villeurbanne, France.
Véricel
E
E
Némoz
G
G
Chen
W
W
Chapuy
P
P
Lagarde
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001792:Blood Platelets / Q000201:enzymology*; D005979:Glutathione Peroxidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006801:Humans; D007118:Immunoassay; D007525:Isoelectric Focusing; D008970:Molecular Weight
D005979:Glutathione Peroxidase