No abstract

Phospholipase A2 treatment of erythrocyte membranes resulted in no detectable release of protein and fatty acids, but between 5 and 10% of the lipid phosphorus was released from the membranes. The overall helical configurations of the membrane proteins as determined by circular dichroism measurements appeared unchanged. Investigation

The action of phospholipase C(EC 3.1.4.3) on erythrocyte ghosts and submitochondrial particles results in a marked change in the molecular structure of the phospholipid regions of the membrane but in no change in the environments (i.e., structure) of the sulfydryl and tyrosyl residues of the membrane proteins as determined by electron spin resonance "spin label" studies. These results hold true whether the membrane is one containing a relatively high proportion of cholesterol (erythrocyte) or one containing very little cholesterol (mitochondrial). The relevance of these findings to current membrane models is discussed.

The interaction of procaine with the nonmyelinated nerve axon from the legs of Homarus americanus was found to produce a conformational change in the lipid structure of the membrane. This conformational change was also observed after treatment of the nerve with acetylcholine bromide but not with any of the following local anesthetics:lidocaine, carbocaine, prilocaine, and nupercaine. It was also found that procaine is a potent inhibitor of acetylcholinesterase whereas the other anesthetics at the same concentration had little effect.