title: Calcium-activated neutral protease in the peripheral nerve, which requires microM order Ca2+, and its effect on the neurofilament triplet.
abstract: There are two types of calcium-activated neutral protease (CANP), m-CANP and mu-CANP, following the nomenclature of Suzuki et al to show that each requires mM and microM Ca2+, respectively, for its activation. We found mu-CANP activity in a crude CANP fraction extracted from the peripheral nerve, which degraded the neurofilament (Nf) triplet (200 K, 160 K, 68 K), especially the 160 K component, at Ca2+ concentrations of 50 microM and 0.1 mM. The triplet was degraded in the order of the 160 K, 68 K, and 200 K components, respectively. In addition, the effects of partially purified mu-CANP of rabbit skeletal muscle, purified natural mu-CANP of bovine liver, derived mu-CANP prepared by autodigestion of chicken muscle m-CANP, m-CANP of chicken skeletal muscle, and cathepsin B of rat liver on the Nf were examined. Among the triplet components, the 160 K component was most rapidly degraded by all proteases so far tested. The difference in the effect of mu-CANP and m-CANP or cathepsin B on susceptibility of the 200 K component to degradation might be due to the difference of the relative amounts of enzymes to Nf.
authors.forename: K
authors.initials: K
authors.lastname: Kamakura
authors.forename: S
authors.initials: S
authors.lastname: Ishiura
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Sugita
authors.forename: Y
authors.initials: Y
authors.lastname: Toyokura
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002154:Calpain; D002401:Cathepsin B; D002403:Cathepsins / Q000378:metabolism; D002417:Cattle; D002645:Chickens; D010450:Endopeptidases / Q000378:metabolism*; D007381:Intermediate Filament Proteins; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D016900:Neurofilament Proteins; D009928:Organ Specificity; D010525:Peripheral Nerves / Q000201:enzymology*; D011817:Rabbits; D013045:Species Specificity
chemical_list: D007381:Intermediate Filament Proteins; D007527:Isoenzymes; D016900:Neurofilament Proteins; D002403:Cathepsins; D010450:Endopeptidases; D002154:Calpain; D002401:Cathepsin B; D002118:Calcium