The major dithiothreitol-resistant phospholipase A2 activity present in the cytosol of U937 cells has been purified greater than 200,000-fold by sequential chromatography on phenyl-5PW, heparin-Sepharose CL-6B, high-performance hydroxylapatite, TSK-gel G3000-SW, and Mono Q columns. This 110-kDa cytosolic phospholipase A2 is distinct from the relatively small (14-kDa) dithiothreitol-sensitive ph...

A specific phospholipase A(2) receptor from porcine cerebral cortex has been characterized (K(d) = 145 nM, B(max) = 0.4 pmol/mg membrane protein) by using a radioiodinated derivative of ammodytoxin C (AtxC), a snake venom presynaptically neurotoxic group IIA phospholipase A(2). After the receptor was solubilized in a ligand-binding form, it was approximately 14,000-fold enriched by chromatograp...

Phospholipase A2 (PLA2) catalyzes the hydrolysis of the SN-2 acyl ester linkage of phospholipids and producing fatty acids and lysophospholipids. Their activity is one of the rate-limiting steps in the formation of arachidonic acid and in the synthesis of leukotrienes and prostaglandins. These prostaglandins have vital role in carcinogenesis. In the present study structure based drug design app...

A phospholipase C which hydrolyzes [14C]phosphatidylcholine has been purified 1782-fold from 70% ammonium sulfate extract of bull seminal plasma. Purification steps included acid precipitation, chromatography on DEAE-Sephacel, concanavalin A, octyl-Sepharose 4B and Ultrogel AcA 34. The final step provided homogeneous phospholipase C as determined by polyacrylamide gel electrophoresis. The enzym...

1. [(32)P]Lecithin and [(32)P]phosphatidylethanolamine were prepared by incubating rat liver mince with [(32)P]phosphate. With these (32)P-labelled phospholipids conditions for the quantitative assay of phospholipase A activity were established. 2. The distribution of phospholipase A activity between subcellular fractions of the bovine adrenal medulla was determined. Phospholipases A(1) and A(2...

Freeze-thawing of microsome-enriched membranes from living bark tissues of black locust trees, especially those from less hardy tissues, caused a drastic increase in sensitivity to Ca(2+) and a complete loss of the regulatory action of Mg(2+) in membrane-bound phospholipase D activity with endogenous (membrane-bound) substrates. Also, the freeze-thaw cycle made phospholipase D in these membrane...

Recent studies have indicated that repeated brief episodes of ischemia and reperfusion render the myocardium more tolerant to subsequent lethal ischemic injury. In view of the previous observations that ischemia-reperfusion potentiates phospholipase D signaling and that such signaling is beneficial for the heart, we investigated whether a similar phospholipase D signaling is responsible for the...

The paper by Sykes et al. (1) on the effect of phospholipase C on high-molecular-mass alkaline phosphatase in serum contains nomenclatural errors. In the Abstract, an Enzyme Comnussion number (EC 3.1.4.3) is given for the phospholipase C of Bacillus cereus; this is not the Enzyme Commission number of the phospholipase C responsible for the effect reported (i.e., the release of liver alkaline ph...

We have examined the effects of phospholipase C from Bacillus cereus (Bc) and from Clostridium perfringens (Cp) on various parameters involved in the activity and response of adenylate cyclase to glucagon in rat liver plasma membranes. A crude preparation of Cp-phospholipase C hydrolyzes “neutral” phospholipids (phosphatidylcholine, phosphatidylethanolamine, sphingomyelin) in these membranes. I...