Myosin light chains of avian and mammalian slow muscles: peptide mapping of 2S light chains

The 2S light chains of mammalian and avian slow muscle myosin, indistinguishable by two-dimensional gel electrophoresis, have been examined by peptide mapping. The fragments obtained with S. aureus V8 protease were analysed either by gel electrophoresis or by reverse-phase high performance liquid chromatography. The peptide maps of avian 2S light chains contain fragments distinct from those of mammalian 2S light chains. Chicken and turkey LC2S appear to be more similar to each other than those from mammalian species (rat and rabbit). These results are in agreement with the relative phylogenetic distances among the four species studied here. The 2S light chain of slow muscle represent further examples of polypeptides which comigrate in two-dimensional gel electrophoresis in spite of their different peptide maps.