Activity of platelet-activating factor acetylhydrolase exists in red cell membrane.
We have described the intracellular type of platelet-activating factor acetylhydrolase (PAF-AH) in the membrane extract of human red blood cells (RBCs). The enzymatic activity was inhibited by diisopropylfluorophosphate, trypsin or pronase E, but not affected by EDTA or the addition of 1-O-hexadecyl-2-hexadecanoyl-rac-glycero-3-phosphocholine or 1-O-hexadecyl-2-[(cis)-9-octadecenoyl]-rac-glycero-3-phosphocholin e. The activity in 10 healthy volunteers was 3.89 +/- 3.26 pmol/10(9) RBCs/min (or 148 +/- 73 nmol/g protein/min) (mean +/- SD). Since PAF-AH is also known to hydrolyze oxidized derivatives of phosphatidylcholine and since RBCs are not effector cells of PAF, the observed activity in RBC membranes may play a potential role in degrading oxidation products of membrane phospholipids.
Yoshida
H
H
Department of Pathologic Physiology, Hirosaki University School of Medicine, Japan.
Satoh
K
K
Imaizumi
T
T
D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D004910:Erythrocyte Membrane / Q000201:enzymology*; D006801:Humans; D010741:Phospholipases A / Q000097:blood*; D010972:Platelet Activating Factor / Q000378:metabolism*
D010972:Platelet Activating Factor; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase