title: Susceptibility of myelin proteins to a neutral endoproteinase: the degradation of myelin basic protein (MBP) and P2 protein by purified bovine brain multicatalytic proteinase complex (MPC).
abstract: Multicatalytic proteinase complex (MPC) was isolated from bovine brain and the susceptibility of myelin basic protein (MBP) and P2 protein of bovine central and peripheral nervous system was examined. SDS-polyacrylamide electrophoretic analysis of purified MPC revealed protein bands of molecular weight ranging from 22-35 kDa. The enzyme is activated by SDS at a concentration less than 0.01%. Upon incubation with MPC, purified MBP and P2 proteins were degraded into smaller fragments. There was a 57% and 100% loss of MBP at 2 and 6 hours of incubation. The P2 protein which is not susceptible to any endogenous non-lysosomal enzyme thus far studied was digested into small peptide fragments only in the presence of SDS (0.01%) and not in its absence. These results indicate that MPC which is active at physiological conditions may have a role in the turnover of myelin proteins and in demyelinating diseases.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002135:Calcium-Binding Proteins / Q000494:pharmacology; D002364:Caseins / Q000378:metabolism; D002417:Cattle; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D015151:Immunoblotting; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000378:metabolism*; D004676:Myelin Basic Protein / Q000378:metabolism*; D018996:Myelin P2 Protein; D011480:Protease Inhibitors / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex
chemical_list: D002135:Calcium-Binding Proteins; D002364:Caseins; D003902:Detergents; D004151:Dipeptides; D007461:Iodoacetates; D009097:Multienzyme Complexes; D004676:Myelin Basic Protein; D018996:Myelin P2 Protein; D011480:Protease Inhibitors; C026018:azocasein; C071482:calpeptin; C033668:calpastatin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D019807:Iodoacetic Acid