Results obtained in this laboratory clearly indicate that myelin proteolipid protein is readily acylated after injection of (3H) fatty acids. Our next goal will be to ascertain the polypeptide with which fatty acids are associated in the macromolecule structure of proteolipid protein. Myelin proteins labelled with 3H fatty acids will be subjected to SDS electrophoresis and the proteolipid protein purified by repeated cycling of SDS gel electrophoresis. The purified proteolipid protein will be treated with cyanogen bromide in 70% formic acid (cyanogen bromide specifically cleaves the protein at methionyl residue) and the resulting polypeptides will be separated by linear gradient (6-20% acrylamide) SDS gel electrophoresis and subjected to fluorography in order to determine the radioactivity associated with the particular cyanogen bromide fragments. The cyanogen bromide fragments of PLP containing the radioactivity will be purified by preparative slab gel electrophoresis and cyanogen bromide peptide will be subjected to Edman-degradation using an automatic amino acid sequencer to ascertain the covalent linkage of 3H fatty acids with specific amino acid(s).