title: Degradation of myelin basic protein by calcium-activated neutral protease (CANP) in human brain and inhibition by E-64 analogue.
abstract: A calcium-activated neutral protease (CANP) was extracted from human brain and partially purified. The activity was measured using alkali-denatured casein (Hammersten) as a substrate. The optimum pH was around 7.0. The activity required the presence of calcium ions, maximum activity was obtained with over 5 mM calcium ions. The Km for the casein concentration was about 1.62 mg/ml. The activity of CANP was inhibited by one of the thiol protease inhibitors, E-64 analogue (E-64-a). The rate of inhibition was about 50% at an E-64-a concentration of 10(-5)M. This CANP degraded selectively basic protein in myelin proteins and the degradation was inhibited by E-64-a or EGTA. The role of the brain CANP in the process of demyelination was suggested by this study.
mesh_terms: D001921:Brain / Q000201:enzymology*; D002154:Calpain; D010450:Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D007930:Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004676:Myelin Basic Protein / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology
chemical_list: D004676:Myelin Basic Protein; D011480:Protease Inhibitors; C034323:EP 459; D010450:Endopeptidases; D002154:Calpain; D007930:Leucine; C024974:E 64