Activation mechanism of calcium-activated neutral protease. Evidence for the existence of intramolecular and intermolecular autolyses.
The activation mechanism through limited autolysis of a calcium-activated neutral protease (CANP) with a high sensitivity to calcium ions (microCANP) was analyzed. The rate of autolysis was dependent on microCANP concentration. The reaction was inhibited by high concentrations of digestible substrates but not by a nondigestible substrate. Incubation of microCANP inactivated by N-ethylmaleimide with a small amount of activated microCANP caused the degradation of the former in a manner similar to the autolysis of native microCANP. Immobilized microCANP bound to an anti-microCANP immunoglobulin G column autolyzed on addition of calcium ions. These results show that activation of microCANP through limited autolysis involves both intramolecular and intermolecular reactions.
Inomata
M
M
Department of Biochemistry, Tokyo Metropolitan Institute of Gerontology, Japan.
Kasai
Y
Y
Nakamura
M
M
Kawashima
S
S
D000818:Animals; D002154:Calpain / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D005033:Ethylmaleimide / Q000494:pharmacology; D006023:Glycoproteins / Q000302:isolation & purification / Q000502:physiology; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology; D011817:Rabbits
D006023:Glycoproteins; C039304:calpain inhibitors; D002154:Calpain; D005033:Ethylmaleimide