FATTY ACIDS AS REGULATORS OF CELL MEMBRANE FUNCTIONS 495 II II EFA (-) EFA (-I-) •1 II n 1,6 n [,6 Figure 3. Schematic representation by Morero et al. (6) of experiments relating to the allosteric transition of erythrocyte acetylcholinesterase in fat- deficient rats. The allosteric behaviour of acetylcholinesterase from red cell ghosts of rats fed fat-sufficient or fat-deficient diets was investigated. Allosteric-type kinetics with n = - 1.6 have been obtained for the inhibition by F- in rats fed a fat-sufficient diet. Values of n shifted to 1.0 (no allosteric effect) in fat- deficient animals (Experiment A). Two types of changes in the value of n were observed in vitro in fat-deficient rats: from - 1.0 to - 1.6 by solubilization of the membrane-bound enzyme (Experiment B) and from -1.6 to -1.0 by reconstitution of the membrane-like structure (Experiment C).

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