Synthetic myelin basic protein peptide analogs are specific inhibitors of phospholipid/calcium-dependent protein kinase (protein kinase C).
Synthetic peptide analogs of the bovine myelin basic protein (MBP) corresponding to residues 104-118 were found to specifically inhibit phospholipid/ Ca2+-dependent protein kinase (protein kinase C). The peptides [Ala107]MBP (104-118) and [Ala113]MBP (104-118) inhibited protein phosphorylation of intact MBP, histone H1 and peptide phosphorylation with MBP(104-123), MBP(104-118) or [Ala105]MBP (104-118) as substrates. The inhibitor peptides [Ala107]MBP(104-118) and [Ala113]MBP (104-118), containing alanine in place of the arginine recognition sites, apparently inhibited the enzyme noncompetitively with respect to substrates, with IC50 values ranging from 46-145 and 28-62 microM, respectively. These peptide analogs did not inhibit cyclic AMP-dependent protein kinase or myosin light chain kinase but inhibited phospholipid/Ca2+-dependent phosphorylation of endogenous proteins in the total, solubilized fraction of rat brain.
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D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology; D002417:Cattle; D007700:Kinetics; D004676:Myelin Basic Protein / Q000138:chemical synthesis* / Q000494:pharmacology; D009219:Myosin-Light-Chain Kinase; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors; D051381:Rats
D004676:Myelin Basic Protein; D010446:Peptide Fragments; D047428:Protein Kinase Inhibitors; D011493:Protein Kinase C; D009219:Myosin-Light-Chain Kinase