Activation of rabbit skeletal muscle adenosine-3':5'-monophosphate-dependent protein kinase by agitation.

Protein kinase activity in a preparation from rabbit skeletal muscle (Wastila, W.B., Stull, J.T., Mayer, S.E., and Walsh, D.A. (1971)J. Biol. Chem. $\text{246}$, 1996–2003.) was increased appr. 15-fold after a 30 to 40 sec agitation of the incubation mixture on a Vortex mixer in either the presence or absence of the protein substrate, histone. Saturating concentrations of adenosine-3′:5′-monophosphate (cAMP) stimulated the activity appr. 23-fold. 0.1% Triton X-100, present during the agitation, completely prevented agitation-induced activation, but left cAMP-dependent activation unaffected.