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SUMMARYThe leakage from hposomes preloaded with glucose was continuously monitored in a Perkin-Elmer Model 356 dual beam spectrophotometer using an enzyme-hnked assay system. The central nervous system myelin basic protein (A 1 protein) caused a 3-4-fold increase in the rate of leakage from liposomes prepared from either central or peripheral nervous system lipids and also from an egg lecithin-5 % phosphatidic acid mixture. Some basic proteins, lysozyme, cytochrolire c, two peripheral nerve myelin basic proteins, trypsin and the tryptic peptides derived from the A 1 protein did not alter glucose leakage from the central nervous system lipid mixture. Other basic proteins, poly L-lysine, protamine sulphate and a reduced, "arginine-rich" histone from bull sperm had a "lytic action" on these liposomes Basic proteins derived from both central and peripheral nervous myehn reduced the poly L-lysine-stimulated leak of the central nervous system liposomes whereas lysozyme had no effect. Additional evidence suggesting a strong interaction of the A 1 protein with liposomes was provided by studies of the action of trypsin on the liposome-protein complexes. The glucose leak of central and peripheral nervous liposomes complexed with A 1 protein was reduced by incubation with trypsin, but was still significantly higher than leakage of these liposomes before the addition of the A 1 protein.

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SUMMARYTwo basic proteins were purified from the peripheral nervous system. The isolation was achieved by (I) delipidation with chloroform-butanol mixtures, dry acetone, and dry ether, (2) acid extraction at pH 2 and then (3) dialysis against distilled water, lyophilization, and solubilization in pH-Io.7 buffer. Further purification steps included: (4) ion exchange chromatography on QAE-Sephadex G-25 and (5) gel filtration on Sephadex G-75. Each of the two basic proteins was shown to be homogeneous by disc electrophoresis at pH 2.0, 4.3, and 9.2.The acid extractable proteins of an isolated fraction from peripheral nerve were studied by using gel filtration and disc electrophoresis techniques. Two basic proteins were also recovered in this case. These proteins gave the same elution volumes and the same electrophoretic mobility as the basic proteins recovered from peripheral nerve. Myelin was extracted with butanol and 72-86 % of the myelin proteins were recovered as soluble lipoproteins. They were compared to the acid extractable proteins.

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