title: Inhibition of platelet factor XIIIa-catalyzed reactions by calmodulin.
abstract: Calmodulin was found to exhibit an inhibitory effect on platelet factor XIIIa-catalyzed incorporation of pseudodonor amines into dimethylcasein, platelet actin and myosin. The inhibitory action of calmodulin on the calcium-dependent enzyme reactions was analogous to the effects of EGTA and parvalbumin on these reactions. The extent of inhibition of factor XIIIa activity was a function of calmodulin concentration when factor XIII and Ca2+ concentrations were held constant. These results indicate that calmodulin inhibits platelet factor XIIIa-catalyzed reactions by sequestering calcium.
mesh_terms: D000199:Actins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000494:pharmacology*; D002364:Caseins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005176:Factor XIII / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006632:Histamine / Q000378:metabolism; D006801:Humans; D009218:Myosins / Q000378:metabolism; D011503:Transglutaminases
chemical_list: D000199:Actins; D002147:Calmodulin; D002364:Caseins; C002087:N,N-dimethylcasein; D006632:Histamine; D005176:Factor XIII; D011503:Transglutaminases; D009218:Myosins; D002118:Calcium