Subcellular localization of enzymes related to PAF metabolism in Krebs-II ascites cells: evidence for the lack of intracellular PAF transfer activity.
We have investigated various steps in the metabolism of Platelet-Activating Factor (PAF-acether or PAF) at the subcellular level in Krebs-II ascites cells. Microsomes contained an active acetyltransferase located on a heavy-rough domain of the endoplasmic reticulum quite rich in ribosomes, as monitored by [3H]uridine labelling, and which displayed a very high density across the Percoll gradient. This membrane domain, which was separated from all other cellular organelles including peroxisomes, also contained a membrane-bound acetylhydrolase with similar activity as the acetyltransferase. However most part of the cellular acetylhydrolase was located in the cytosol, which was actually devoid of PAF transfer activity, normally involved in transport of the mediator within the cell.
Ribbes
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Institut National de la Santé et de la Recherche Médicale, Unité 326, Hôpital Purpan, Toulouse, France.
Gelas
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P
Lumb
R
R
Record
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Terce
F
F
Chap
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H
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D001201:Ascites / Q000201:enzymology*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004721:Endoplasmic Reticulum / Q000201:enzymology; D007425:Intracellular Membranes / Q000201:enzymology; D051379:Mice; D008861:Microsomes / Q000201:enzymology; D010972:Platelet Activating Factor / Q000378:metabolism*
D010972:Platelet Activating Factor; D000123:Acetyltransferases