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Characterization of a Novel Phospholipase A 2 Activity in Human Brain
Author(s) -
Ross Brian M.,
Kim Dae K.,
Bonventre Joseph V.,
Kish Stephen J.
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.64052213.x
Subject(s) - phospholipase a2 , chemistry , biochemistry , enzyme , arachidonic acid , human brain , enzyme assay , phospholipase a , phospholipase , biology , neuroscience
Phospholipases A 2 (PLA 2 ) are a family of enzymes that catalyze the removal of fatty acid residues from phosphoglycerides. The enzyme is postulated to be involved in several human brain disorders, although little is known regarding the status of PLA 2 activity in human CNS. We therefore have characterized some aspects of the PLA 2 activity present in the temporal cortex of human brain. More PLA 2 activity was found in the membrane (particulate) fraction than in the cytosolic fraction. The enzyme could be solubilized from particulate material using 1 M potassium chloride, and was capable of hydrolyzing choline phosphoglyceride (CPG) and ethanolamine phosphoglyceride (EPG), with a preference (approximately eightfold) for EPG over CPG. When the solubilized particulate enzyme was subjected to gel filtration chromatography, PLA 2 activity eluted in a high molecular mass fraction (∼180 kDa). PLA 2 activity was weakly stimulated by dithiothreitol, strongly stimulated by millimolar concentrations of calcium ions, and inhibited by brief heat treatment at 57°C, bromophenacyl bromide, the arachidonic acid derivative AACOCF 3 , γ‐linolenoyl amide, and N ‐methyl γ‐linolenoyl amide. Thus, whereas the human brain enzyme(s) characterized in our study displays some of the characteristics of previously characterized PLA 2 s, it differs in several key features.