Using our own new modification of one-dimensional sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) we successfullyseparated myosin heavy chains from different chambers of rat heart.The key features of modification are changes in the content andbuffer composition of the separating gel, and employment of constantcurrent instead of voltage. These changes allow carrying out a saferand faster one-dimensional SDS-PAGE for cardiac myosin heavy chainsusing significantly fewer reagents.