Metal ion stimulation of phospholipase D-like activity of isolated rat intestinal mitochondria.
Presence of phospholipase D-like (PLD) activity in the intestinal mitochondria was identified using endogenous phospholipids as substrate. The enzyme had a pH optimum of 6.5, did not show trans-phosphatidylation activity in the presence of ethanol or butanol, and the product formed was phosphatidic acid (PA). This was confirmed by separation of reaction products by high-performance liquid chromatography and analysis of composition of the PA formed which gave phosphate/fatty acid ratio of 1:2 PLD-like activity was further confirmed by the formation of ethanolamine and choline as products of enzyme action. This activity was stimulated by various metal ions; when stimulated by Mg2+ and Ba2+, it hydrolyzed both phosphatidylcholine and phosphatidylethanolamine, and when stimulated by Ca2+, it preferentially hydrolyzed phosphatidylethanolamine. There was no requirement for sodium oleate for the PLD-like activity in mitochondria. These results suggest that intestinal mitochondria have an active PLD-like enzyme which differs in certain properties from phospholipase D from other tissues.
Madesh
M
M
Wellcome Trust Research Laboratory, Department of Gastrointestinal Sciences, Christian Medical College & Hospital, Vellore, India.
Balasubramanian
K A
KA
D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D002794:Choline / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D019856:Ethanolamine; D004983:Ethanolamines / Q000378:metabolism; D005470:Fluorometry; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000187:drug effects / Q000201:enzymology*; D008670:Metals / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D010712:Phosphatidic Acids / Q000737:chemistry / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats
D002413:Cations, Divalent; D004983:Ethanolamines; D008670:Metals; D010712:Phosphatidic Acids; D010743:Phospholipids; D019856:Ethanolamine; D010739:Phospholipase D; D002794:Choline