Phosphorylated heavy meromyosin had a 2.5-times weaker binding affinity for F-actin in the presence of Ca2+, whereas dephosphorylated HMM had a 2.4-times higher affinity.
The effect of myosin light chain phosphorylation in skeletal muscle was investigated with respect to the binding affinity of phosphorylated and dephosphorylated heavy meromyosin (HMM) for F-actin in the absence of ATP. For phosphorylated HMM the affinity was 2.5-times weaker in the presence of Ca2+ as in its absence (HMM divalent binding sites saturated only with Mg). For dephosphorylated HMM the reverse was true, the binding being 2.4-times higher in the presence of Ca2+.
Szczçsna et al. (Mon,) reported a other. Phosphorylated heavy meromyosin (HMM) vs. Dephosphorylated heavy meromyosin (HMM) was evaluated on Binding affinity for F-actin in the absence of ATP. Phosphorylated heavy meromyosin had a 2.5-times weaker binding affinity for F-actin in the presence of Ca2+, whereas dephosphorylated HMM had a 2.4-times higher affinity.