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...

A granule-associated phospholipase A2 from rabbit polymorphonuclear leukocytes and a closely similar phospholipase A2 from rabbit serum have been purified to near homogeneity by ion-exchange and reverse-phase chromatography. The cellular (polymorphonuclear leukocyte) phospholipase A2 has been purified greater than 100,000-fold and the extracellular (serum) phospholipase A2 approximately 60,000-...

Pancreatic phospholipase A2 and non-pancreatic ascitic phospholipases A2 were studied in sera of healthy individuals and of patients suffering from sepsis or acute pancreatitis. In gel filtration experiments, immunoreactive ascitic phospholipase A2, as determined in serum by a time-resolved fluoroimmunoassay, eluted either unassociated with an apparent M(r) of 10,000-14,000 or associated with p...

Immunoreactive phospholipase A2 (EC 3.1.1.4) was measured by a new sensitive time-resolved fluoroimmunoassay in the serum of 58 healthy subjects and 103 patients with acute pancreatitis. Patients with acute pancreatitis were grouped according to the etiology and clinical severity of the disease. The mean phospholipase A2 concentration in the reference (healthy) group was 5.5 (SD 1.9) micrograms...

introduction: in a serious brain disorder like alzheimer's disease, the levels of acetylcholine (ach) drop significantly. the gradual death of cholinergic brain cells leads to a profound loss of memory and learning ability. acetylcholine is the chemical messenger that sends messages from one neuron to another in the area of the brain used for memory. many of the current medications act to ...

The proliferative properties and the ability to stimulate the Na+/H+antiport activity of a secretory phospholipase A2 were studied in rat aortic smooth muscle cells in culture. The requirement of the enzymatic activity of phospholipase A2 to elicit mitogenesis was assessed by the use of ammodytin L, a Ser49 phospholipase A2 from the venom of Vipera ammodytes, devoid of hydrolytic activity. We p...

Crosslinking of the antigen receptors on the immature B-cell lymphoma, WEHI-231, leads to growth arrest and apoptosis. Commitment to such B-cell receptor (BCR)-mediated apoptosis correlates with mitochondrial phospholipase A2 activation, disruption of mitochondrial function, and cathepsin B activation. CD40 signaling has been reported to rescue WEHI-231 B cells from BCR-driven apoptosis primari...

We examined the effect of diacylglycerol on Ca2+-dependent phospholipase A2 from human platelets. Phospholipase A2 was solubilized and partially purified to a stable form in the presence of n-octyl beta-D-glucopyranoside (octyl glucoside), and its enzymic activity was determined with sonicated 2.5 microM-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (arachidonoyl-PC) as substrate. Phos...