Phospholipase A2 -catalyzed hydrolysis of lecithin in a continuous reversed-micellar membrane bioreactor

1996 ◽  
Vol 73 (3) ◽  
pp. 337-346 ◽  
Author(s):  
M.A.P. Morgado ◽  
J.M.S. Cabral ◽  
D.M.F. Prazeres
Keyword(s):  
Phospholipase A2 ◽  
Membrane Bioreactor ◽  
Hydrolysis Of

Hydrolysis of intralipid by pancreatic lipase and phospholipase A2-gel filtration studies

Lipids ◽  
1985 ◽  
Vol 20 (11) ◽  
pp. 765-772 ◽  
Author(s):  
Renée Grataroli ◽  
Monique Charbonnier ◽  
Gilles Nalbone ◽  
Denis Lairon ◽  
Christiane Chabert ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Pancreatic Lipase ◽  
Gel Filtration ◽  
Hydrolysis Of

scholarly journals Modulation of human type II secretory phospholipase A2 by sphingomyelin and annexin VI

1997 ◽  
Vol 326 (1) ◽  
pp. 227-233 ◽  
Author(s):  
Kamen KOUMANOV ◽  
Claude WOLF ◽  
Gilbert BÉREZIAT
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Phospholipase A2 ◽  
Cell Membranes ◽  
Red Cell ◽  
Type Ii ◽  
Membrane Phospholipids ◽  
Human Type ◽  
Annexin Vi ◽  
Hydrolysis Of

Conjectural results have been reported on the capacity of inflammatory secreted phospholipase A2 (sPLA2) to hydrolyse mammalian membrane phospholipids. Development of an assay based on the release of non-esterified fatty acids by the enzyme acting on the organized phospholipid mixture constituting the membrane matrix has led to the identification of two prominent effectors, sphingomyelin (SPH) and annexin. Recombinant human type II sPLA2 hydrolyses red-cell membrane phospholipids with a marked preference for the inner leaflet. This preference is apparently related to the high content of SPH in the outer leaflet, which inhibits sPLA2. This inhibition by SPH is specific for sPLA2. Cholesterol counteracts the inhibition of sPLA2 by SPH, suggesting that the SPH-to-cholesterol ratio accounts in vivo for the variable susceptibility of cell membranes to sPLA2. Different effects were observed of the presence of the non-hydrolysable D-α-dipalmitoyl phosphatidylcholine (D-DPPC), which renders the membranes rigid but does not inhibit sPLA2. Annexin VI was shown, along with other annexins, to inhibit sPLA2 activity by sequestering the phospholipid substrate. The present study has provided the first evidence that annexin VI, in concentrations that inhibit hydrolysis of purified phospholipid substrates, stimulated the hydrolysis of membrane phospholipids by sPLA2. The activation requires the presence of membrane proteins. The effect is specific for type II sPLA2 and is not reproducible with type I PLA2. The activation by annexin VI of sPLA2 acting on red cell membranes results in the preferential release of polyunsaturated fatty acids. It suggests that type II sPLA2, in conjunction with annexin VI, might be involved in the final step of endocytosis and/or exocytosis providing the free polyunsaturated fatty acids acting synergistically to cause membrane fusion.

Hydrocortisone inhibits mucin secretion from guinea pig gallbladder

1984 ◽  
Vol 247 (4) ◽  
pp. G427-G431 ◽  
Author(s):  
J. R. Moore ◽  
B. S. Turner ◽  
J. T. LaMont
Keyword(s):  
Guinea Pig ◽  
Phospholipase A2 ◽  
Sodium Succinate ◽  
Inhibitory Effect ◽  
Membrane Phospholipids ◽  
Mucin Secretion ◽  
Basal Secretion ◽  
Prostaglandin Release ◽  
Hydrolysis Of

We studied the effects of hydrocortisone, an inhibitor of phospholipase A2, on the secretion of mucin and release of prostaglandins from guinea pig gallbladder explants. We measured mucin using [3H]glucosamine as a precursor and prostaglandins by radioimmunoassay of 6-keto-prostaglandin F1 alpha. Mucin secretion and prostaglandin release were studied under basal conditions and after arachidonate stimulation. Hydrocortisone sodium succinate reversibly inhibited basal secretion of mucin by 24% at 10(-5) M (P less than 0.05 compared with control) and 34% at 10(-4) M (P less than 0.01). Hydrocortisone, 10(-4) M, also reversibly inhibited arachidonate-stimulated secretion of mucin (P less than 0.01 compared with controls incubated with arachidonate alone). Release of prostaglandin F1 alpha was significantly inhibited by hydrocortisone under basal (P less than 0.01) and arachidonate-stimulated (P less than 0.01) conditions. The inhibitory effect of hydrocortisone was mediated by inhibition of hydrolysis of arachidonate from membrane phospholipids, suggesting that exogenous arachidonate is incorporated into membrane phospholipids prior to conversion to prostaglandins.

scholarly journals Group V Secreted Phospholipase A2 Is Upregulated by IL-4 in Human Macrophages and Mediates Phagocytosis via Hydrolysis of Ethanolamine Phospholipids

2015 ◽  
Vol 194 (7) ◽  
pp. 3327-3339 ◽  
Author(s):  
Julio M. Rubio ◽  
Juan P. Rodríguez ◽  
Luis Gil-de-Gómez ◽  
Carlos Guijas ◽  
María A. Balboa ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Group V ◽  
Human Macrophages ◽  
Secreted Phospholipase A2 ◽  
Hydrolysis Of
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