Cardiac MHC isoform composition. Cardiac MHC isoform composition was assessed by SDS-PAGE electrophoresis (Rundell et al., 2005). (A) Identification of protein bands by Western blot antibody staining. The three lanes shown were loaded with an atrial extract (left lane A; contains mostly α-MHC), a ventricular extract (right lane V; contains mostly β-MHC), and an atrial + ventricular mixture (middle lane A + V). An α-MHC specific antibody (top) only detected bands in the left A and middle A + V lane, while a pan-MHC (total MHC) antibody detected bands in all lanes; here, separation between the two MHC isoforms is evident. (B) Sypro Ruby total protein stain was used to measure MHC composition. Representative lanes of atrial (A), ventricular (V), and A + V are shown for a Sham and AOB cardiac sample. In all samples studied, α-MHC was below the detection limit (n = 3 Sham hearts and n = 3 AOB hearts). Source data are available for this figure: SourceData F5