Characterization of a protein kinase from chicken oviductal fluids

Protein kinase has been found extracellularly in avian oviductal secretions. The enzyme has been isolated and shown to be primarily type II cAMP enhanced. The Ka for cAMP activation, binding and elution from ion-exchange columns, molecular weight of subunits, pH optimum as a histone kinase, response to cations, kinetic properties, and preference for lysine-rich histone are similar to those of mammalian type II protein kinase. Gel filtration data suggest that the dimer form is the functional entity in the reproductive tract. The catalytic subunit has been purified to greater than 90% homogeneity and has a Km of 4 mumol/l and Vmax of 10(6) U/mg, comparable to published values for bovine catalytic subunit.