Seminalplasmin. An endogenous calmodulin antagonist.
Seminalplasmin, a strongly basic protein isolated from bull semen, was found to antagonize with high potency and extraordinary specificity the function of calmodulin. Calmodulin antagonism is the result of an interaction between the two proteins, which is mainly determined by electrostatic forces. The stimulation of Ca2+-transporting ATPase and phosphodiesterase by calmodulin was half-maximally inhibited at approx. 0.1 microM-seminalplasmin. However, the basal activity of calmodulin-dependent enzymes was not significantly altered by seminalplasmin over the concentration range investigated.
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D008297:Male; D010726:Phosphodiesterase Inhibitors; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011506:Proteins / Q000494:pharmacology*; D029607:Seminal Vesicle Secretory Proteins
D002147:Calmodulin; D010726:Phosphodiesterase Inhibitors; D011506:Proteins; D029607:Seminal Vesicle Secretory Proteins; D010727:Phosphoric Diester Hydrolases; D000252:Calcium-Transporting ATPases