Lipid molecular species, retailoring

LIPID MOLECULAR SPECIES RETAILORING UNDER TEMPERATURE STRESS... 

Lynch DV, Thompson GA. Retailored lipid molecular species a tactical mechanism for modulating membrane properties. Trans Biochem Sci 1984 9 442-445. 

Most plants respond to environmental stresses by changes in the lipid composition of their cel 1-membranes. Main transformations, observed in a long term period, are concerned with the phospholipid composition of membranes and the degree of unsaturation of component fatty acids (1). In the short term, some "retailoring" of lipid molecular species (intermolecular rearrangements of lipid acyl chains) can be observed (2). All these chemical changes would result in modifications of the physical state of membrane lipids. 

Phospholipase A2 enzymes also have other important metabolic functions in addition to the overall destruction of phospholipids as catalysed by digestive pancreatic or venom enzymes. An enzyme in mitochondrial membranes seems to be intimately connected with the energy state of this organelle. Thus, the phospholipase is inactive in fully coupled mitochondria and only becomes active when ATP and respiratory control drop to low levels. Also, the widespread distribution of phospholipases A2 allows many tissues to perform retailoring of the molecular species of membrane lipids by the Lands mechanism. In this process, named after Lands, the American biochemist who first described it, cleavage of the acyl group from the sn-2 position yields a lysophospholipid which can be re-acylated with a new fatty acid from acyl-CoA (Figure 7.8). 

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