ELECTROPHORETIC SEPARATION OF RAT SKELETAL-MUSCLE MYOSIN HEAVY-CHAIN ISOFORMS

A new technique for the sodium dodecyl sulfate-polyacrylamide gel elec trophoretic separation of rat skeletal muscle myosin heavy-chain (MHC) isoforms is presented. This technique allows for the separation of th e four identified MHC isoforms known to be present in adult rat skelet al muscle. These types of MHC are commonly called I, IIa, IIx or IId, and IIb. The procedure can be performed using minigel electrophoresis systems and does not involve preparation of gradient-separating gels o r the use of special cooling devices. The procedure accommodates both silver and Coomasie Blue staining. Thus the procedure is simple to per form and highly repeatable, providing high-resolution separation of MH C protein isoforms. The percent composition of the four adult MHCs in rat soleus, medial gastrocnemius, diaphragm, and levator ani muscles b y use of this procedure and Coomasie Blue staining is similar to that previously reported. This new technique provides a novel and easy-to-p erform method for the separation of rat skeletal muscle MHC isoforms.