Basis of microheterogeneity of myelin basic protein.

摘要: The basic protein of bovine central nervous system myelin contains a single polypeptide chain 170 amino acids. Multiple components have been observed on disc gel electrophoresis and ion exchange chromatography at alkaline pH, but the basis microheterogeneity has not established. In present study from spinal cord was chromatographed carboxymethylcellulose pH 10.4 in glycine buffer/2 M urea. Three major peaks were obtained, identified as 4, 5, 6 oder their elution column by linear salt gradient. acid compositions tryptic peptides 4 identical COOH-terminal sequence, Ala-Arg-Arg, intact for all three components. Component found to differ component partial phosphorylation threonine 98 serine 165. This modification estimated account 50% 4. 5 differed deamidation glutamine residues 103 147, which accounted 80% this component. These modified also constituted another 15% It considered that native, unmodified species net negative charge 2, of.1 result these modifications. nonrandom nature modifications suggested involvement specific enzymes.