Isolation of myosin heavy chain from small skeletal muscle samples by preparative continuous elution gel electrophoresis: Application to measurement of synthesis rate in human and animal tissue

A convenient procedure for the isolation of milligram quantities of myosin heavy chain (MHC) from small samples of muscle tissue using preparative gel electrophoresis is described. Application of the methodology to measurements of the fractional synthesis rates (k_s) of MHC using skeletal muscle biopsy samples from humans and cardiac tissue from pigs following continuous intravenous infusions of stable isotope (L-[1-¹³C]-leucine) is demonstrated. The sensitivity and reproducibility of the determination of stable isotope enrichment are also defined. In addition, measurements of the k_s of MHC in skeletal muscle of rats in vivo using radioisotope-tracer methodologies are described.