Release of dialkylglycerol from purple membrane phospholipids by phospholipase D.
When the major polar lipid of purple membrane, a dialkyl analogue of phosphatidyl glycerophosphate, is treated with phospholipase D under the usual assay conditions for this enzyme, the reaction yields dialkylglycerol and glycerol bisphosphate, i.e. the kind of products that would be expected from a phospholipase C reaction. The effect is seen both in native purple membranes and with the pure phospholipid in the form of liposomes. The specific activity and kinetic parameters Km and Vmax of phospholipase D for the purple membrane phospholipid are similar to those for egg phosphatidylcholine. The presence of phospholipase C impurities in the phospholipase D preparations has been ruled out as an explanation for the above observations. A hypothesis is suggested, taking into account the peculiar headgroup structure of the bacterial lipid, to explain the seemingly anomalous enzyme behavior.
Muga
A
A
Department of Biochemistry, University of Basque Country, Bilbao, Spain.
Arrondo
J L
JL
Gurtubay
J I
JI
Goñi
F M
FM
D001409:Bacillus cereus / Q000201:enzymology; D001436:Bacteriorhodopsins / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D004075:Diglycerides / Q000302:isolation & purification*; D005989:Glycerides / Q000302:isolation & purification*; D006217:Halobacterium / Q000378:metabolism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*; D010740:Phospholipases / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D013055:Spectrophotometry, Infrared; D010738:Type C Phospholipases / Q000378:metabolism
D004075:Diglycerides; D005989:Glycerides; D008563:Membrane Lipids; D010743:Phospholipids; D001436:Bacteriorhodopsins; D010740:Phospholipases; D010738:Type C Phospholipases; D010739:Phospholipase D