Immunochemically detected structural difference in the heavy chains of chicken breast muscle myosin isozymes

Antisera against the isozymes of heavy meromyosin from chicken breast muscle myosin were prepared by immunizing rabbits. Both antisera against heavy meromyosin containing g1 light chain (HMM(g1) and that containing g3 light chain (HMM(g3)) reacted with both heavy meromyosin isozymes and myosin, but not with whole light chain mixture. This indicates that only antibodies against the heavy chain of heavy meromysin were elicited. The antisera were applied successively to two columns, one coupled with subfragment-2 and the other with heterologous subfragment-1 isozymes. When the antiserum against HMM(g3) was absorbed with subfragment-1 containing g1 (S-1(g1)), it did not react with HMM(g1), but reacted with HMM(g3). On the other hand, when the antiserum against HMM(g1) was absorbed with subfragment-1 containing g3 (S-1(g3)), it lost its ability to react with both heavy meromyosin isozymes. This indicates the presence of a specific antibody against the heavy chain of HMM(g3). The head portion of myosin containing g3 may hold an unique antigenic determinant which is not present in the head of a myosin containing g1.