Mammalian cells contain many structurally and functionally diverse phospholipases A2 (PLA2) that catalyze the hydrolysis of sn-2 fatty acid from membrane phospholipid. Assays are described for measuring the activity of Group IVA cytosolic PLA2alpha(cPLAalpha) and for secreted PLA2s (sPLA2) that are suitable for purified enzymes and for measuring activity in crude cell lysates and culture medium...

Phospholipase A2 (PLA2) is an enzyme present in snake and other venoms and body fluids. We measured PLA2 catalytic activity in tissue homogenates of 22 species representing the classes Anthozoa, Hydrozoa, Scyphozoa and Cubozoa of the phylum Cnidaria. High PLA2 levels were found in the hydrozoan fire coral Millepora sp. (median 735 U/g protein) and the stony coral Pocillopora damicornis (693 U/g...

Oil bodies (OBs) are lipid-storing organelles of soybean seeds and the source substrates for enzymatic oxidation reaction soymilk flavour formation. However, triacylglycerols (TAGs) in OBs surrounded by a membrane composed phospholipids embedded with integral oleosins to prevent them from being hydrolyzed lipase. Therefore, specific process formation becomes complicated is not well understood. ...

Arachidonoyl-hydrolyzing phospholipase AZ plays a central role in providing substrate for the synthesis of the potent lipid mediators of inflammation, the eicosanoids, and platelet-activating factor. Although Ca2+ is required for arachidonic acid release in vivo and most phospholipase A, enzymes require Ca2’ for activity in vitro, the role of Ca” in phospholipase A2 activation is not understood...

The infection of HeLa cells by poliovirus leads to profound alterations in the activities of both phospholipase C and the A23187-stimulated phospholipase A2. As early as the third hour after poliovirus infection, the activity of phospholipase C is enhanced, as measured by the increase in inositol triphosphate (IP3) in the cells. By the fifth hour post-infection there is a 5-fold increase in IP3...

A photoreactive derivative of phosphatidylethanolamine, N-(4-azidobenzoyl)phosphatidylethanolamine (AB-PE), was synthesized by acylation of phosphatidylethanolamine with an N-hydroxysuccinimide ester of 4-azidobenzoic acid. The substantial photosensitivity exhibited by AB-PE correlated with a marked decrease in the absorption spectra of the compound. The compound proved sensitive to lipase and ...

In isolated rat hepatocytes, mepacrine stimulated the conversion of [1-14C]oleate into 14CO2 and depressed the formation of acid-soluble products from [1-14C]oleate. The action of mepacrine on [1-14C]oleate oxidation was not affected by exogenously applied phospholipase A2 (from Crotalus adamanteus venom) or arachidonic acid. It is suggested that mepacrine may exert its metabolic effects in iso...

Increased concentrations of eicosanoids are found in synovial fluids (SF) from patients with rheumatoid arthritis (RA). SF polymorphonuclear leukocytes (PMN), which derive from peripheral blood, usually account for approximately 90% of the cells in RA SF. Since eicosanoid precursor fatty acids (FA) are liberated by phospholipases from membrane phospholipids, we examined phospholipase A2 and C a...