ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 41, Number 4
JKCSEZ 41(4)
August 20, 1997 

The site specificity of dephosphorylation of myelin basic protein(MBP) was studied in vitro. To assign amino acid site of dephosphorylation, MBP was phosphorylated by protein kinase C(PKC) and dephosphorylated by protein phosphatase PP2A. The phosphorylated MBP was digested by trypsine and the digested peptides were separated by a reverse phase HPLC chromatography. The radioactivity of each fraction was counted and partially sequenced. Seven radioactive peptides were observed and Ser55 in the second peak(P2) shows the best susceptibility for the phosphorylation. However in the dephosphorylation, the fifth peak(P5) appeared to release it's phosphate group most rapidly. This result demonstrates that MBP is a suitable substrate for protein phosphatase.