ISSN:
1432-1424
Keywords:
phospholipase A2
;
phospholipid organization
;
myelin phospholipids
;
synaptic membrane phospholipids
;
liposome hydrolysis
;
phospholipase A2 cofactors
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary The pattern of fatty acid release from rat synaptic membranes in the presence of phospholipase A2 (Vipera russelli) was compared to that from liposomes comprised of phospholipids. Phospholipase A2 more readily attacked myelin and synaptic membranes than liposomes prepared from total phospholipids derived from myelin. Although hydrolysis of liposomal phospholipids occurred in the absence of added calcium, the presence of 2mm CaCl2 or 2% bovine serum albumin significantly enhanced the phospholipase attack of liposomes, but not synaptic membranes or myelin. Phospholipase exhibited a marked preference for phospholipids containing docosahexaenoic acid (22∶6) in the synaptic membranes, while with liposomes the pattern of released fatty acid reflected the fatty acid composition in the two-position of the phospholipids. Although either calcium or albumin markedly increased the phospholipase hydrolysis of liposomes, neither affected the hydrolysis of synaptic membranes or the pattern of fatty acid release from liposomes. It was concluded that the nonlipid constituents, particularly the proteins, of biomembranes were responsible for the organization of the phospholipids and accounted for the observed differences between liposomes and synaptic membranes with respect to enzymic accessibility.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01868476
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