title: Phospholipid-sensitive Ca2+ -dependent protein kinase preferentially phosphorylates serine-115 of bovine myelin basic protein.
abstract: Phospholipid-sensitive Ca2+ -dependent protein kinase (PL-Ca-PK) and cyclic AMP-dependent protein kinase (A-PK) both preferentially phosphorylated serine residues of bovine myelin basic protein (MBP). Tryptic peptide maps of MBP phosphorylated by PL-Ca-PK or A-PK, however, revealed different phosphopeptides, suggesting a difference in the intramolecular substrate specificity for the two enzymes. Serine-115 of MBP, in the sequence (-Arg-Phe-Ser(115)-Trp-), was found to be a preferred and probably major phosphorylation site for PL-Ca-PK. Because serine-115 of bovine MBP corresponds to serine-113 of rabbit MBP, an in vivo phosphorylation site reported by Martenson et al. (1983), and PL-Ca-PK is present at a very high level in brain and myelin, it is suggested that the enzyme may be responsible for the in vivo phosphorylation of this and other sites in MBP.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D000242:Cyclic AMP / Q000494:pharmacology; D004676:Myelin Basic Protein / Q000378:metabolism*; D010743:Phospholipids / Q000494:pharmacology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine
chemical_list: D004676:Myelin Basic Protein; D010743:Phospholipids; D012694:Serine; D000242:Cyclic AMP; D011494:Protein Kinases; D002118:Calcium