Myosin essential light chain 1sa decelerates actin and thin filament gliding on β-myosin molecules.

The β-myosin heavy chain expressed in ventricular myocardium and the myosin heavy chain (MyHC) in slow-twitch skeletal Musculus soleus (M. soleus) type-I fibers are both encoded by MYH7. Thus, these myosin molecules are deemed equivalent.