Jansen GJ, Pritzker CR, Deykin D. Porcine aortic endothelial cell membranes contain a LPAF: CoA-independent transacylase.
BIOCHIMICA ET BIOPHYSICA ACTA 1993;
1145:113-8. [PMID:
8422403 DOI:
10.1016/0005-2736(93)90387-f]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Membranes isolated from porcine aortic endothelial cells (PAEC) contain a CoA-independent transacylase enzyme (CoA-IT). CoA-IT, an integral membrane protein, transfers an acyl moiety to added [3H]alkylhydroxyglycerophosphocholine (LPAF) to generate [3H]alkylacylglycerophosphocholine (alkylacyl-GPC). This enzyme exhibits an apparent Km of 0.7 microM and a Vmax of 0.8 nmol/min per mg for the transfer of an acyl group to added [3H]LPAF. The addition of the nonionic detergent Triton X-100 (TX-100) (0.5 mg/ml), the sulfhydryl reagents N-ethylmaleimide (NEM) (200 microM) or thimerosal (200 microM), or pre-incubating the membranes at 95 degrees C for 10 min all decreased LPAF: CoA-IT activity by more than 95%. The inhibitory action of NEM or thimerosal suggests that sulfhydryl group(s) are involved in or are close to the catalytic site of LPAF: CoA-IT.
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