Line defects in gel phase lipid monolayers.
We investigate various models of the hydrolysis of gel-phase phosphatidylcholine monolayers by phospholipase A2 (Grainger et al. (1989) FEBS Lett. 252, 73-82). We assume that the probability of hydrolysis of a given lipid depends only upon how many of its nearest neighbour lipids have already been hydrolysed. We find that the experimental data are consistent with a model in which line defects exist in the gel phase and that lipids on such defects are more easily hydrolysed than the other gel-phase lipids. Based on this model, we calculate the course of hydrolysis of a gel-phase region possessing line defects, and we suggest how such a structure might be made and the model tested. An experiment, similar to that proposed by us, has been carried out by Grainger et al. (1990) Biochim. Biophys. Acta 1023, 365-379). We also calculate the fractal dimension, df, of the interface created by the hydrolytic process and show that a measurement of df might identify how this process proceeds.
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Theoretical Physics Institute, St. Francis Xavier University, Antigonish, Nova Scotia, Canada.
Farrell
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MacNeil
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Sackmann
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D003198:Computer Simulation; D006868:Hydrolysis; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D010713:Phosphatidylcholines / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2
D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010741:Phospholipases A; D054467:Phospholipases A2