because trypsin digestion of mlck cleaves off not only the ca2+/calmodulin-binding site but also the site phosphorylated by camp-dependent protein kinase , and because mg2+ activation of cone contraction circumvents mlck action altogether , both these observations would be expected if camp inhibits reactivated cone contraction by catalyzing the phosphorylation of mlck and thus reducing its affinity for ca2+ , as has been described for smooth muscle .
C0031715
phosphorylation
C0027120
mlck