Calmodulin-stimulated particulate guanylate cyclase in crayfish hepatopancreas.
1. A particulate guanylate cyclase from crayfish hepatopancreas membranes was investigated with respect to its dependence on Ca2+ and calmodulin. Addition of Ca2+ to EGTA-treated membranes increased cyclase activity by 100%. 2. Calmodulin stimulated the activity about 5-fold. 3. This effect could be abolished by the calmodulin antagonist compound 48/80. 4. These results present evidence that the particulate guanylate cyclase of crayfish hepatopancreas is a Ca2+/calmodulin-dependent enzyme. 5. The implications of this observation upon glycogen metabolism of crustaceans are discussed.
Riediger
W
W
Institut für Zoophysiologie, Universität Bonn, B.R.D.
Hergenhahn
H G
HG
Sedlmeier
D
D
D000818:Animals; D003400:Astacoidea / Q000201:enzymology*; D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000502:physiology*; D004789:Enzyme Activation; D006162:Guanylate Cyclase / Q000302:isolation & purification / Q000378:metabolism*; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology; D008297:Male; D010179:Pancreas / Q000201:enzymology
D002147:Calmodulin; D006162:Guanylate Cyclase; D002118:Calcium