FIGURE 9.

Toad heart expresses cardiac MHC. A, MHC isoforms in the hearts and skeletal muscles of toad, frog, and Xenopus were resolved in glycerol/SDS gel. Mouse diaphragm muscle was analyzed in parallel as control. A single MHC band was detected in toad heart with a slightly different gel mobility from that of frog cardiac MHC or the MHC bands in toad rectum abdominis and sartorius muscles. B, mAb FA2 specific to cardiac α- and β-MHC (cardiac β-MHC is the same as MHC I in slow skeletal muscle) recognized the MHC band in both toad and frog hearts, supporting their nature as cardiac MHC.