SIsolation and characterization of "L17" light chain of myosin from bovine uterine smooth muscle

Phylogenetic studies of cardiac myosins from amphibia to mammals

Comparison between pig atrial and ventricular myosins was performed on the light chains (using SDS-PAGE) and on the heavy chains (using Ca2+-ATPase measurements and NTCBA peptide mapping). Light chain composition of pig cardiac myosins was compared to three other species ones (frog, chicken and human). Up to birds, atrial and ventricular myosin light chain composition was identical whereas in mammals atrial and ventricular myosin light chain composition was different; likewise the heavy chains. Six cardiac myosin isoenzymes have been thus characterized. No correlation can be established between cardiac myosin light chain pattern and species evolution.

Perineal rhabdomyosarcoma in a newborn child: pathological and biochemical studies with emphasis on contractile proteins

Histological and ultrastructural studies have been undertaken on a perineal rhabdomyosarcoma from a newborn child. The spontaneous tumour has the typical feature of mesenchymoma. The recurrent tumour, however, displays some rhabdopoietic characteristics. The myosin of the recurrent tumour has been extracted and compared with human fetal myosin. These two myosins are identical in their synthetic filaments and their light-chain composition. Nevertheless, whereas the ATPase activity of fetal myosin can be stimulated considerably by increasing the ca2+ concentration, that of tumoral myosin remains very low. These results show that there are isoenzymes of myosins and there must be differences in the myosin heavy chains, particularly in the active sites. These findings are identical with those seen in experimental rhabdomyosarcoma.

[Isolation of myosin light chain from porcine heart by preparative electrophoresis and study of the polypeptides obtained by cyanogen bromide action]

A simple, rapid and efficient procedure is developed to isolate proteins with identical or different isoelectric points such as pig cardiac myosin light chains. Preparative electrophoresis on discontinuous polyacrylamide slab gels in the presence of urea allows a very good separation of each light chain (L27 and L18) and heavy chain from highly purified myosin. An original elution procedure of the proteins fixed and localized by amido schwartz allows the isolation of the L27 and L18 light chains in quantities sufficient to carry out structural studies. Homogeneity of light chains thus isolated is checked by the analysis of cyanogen bromide peptides. Structural similarities can be demonstrated between myosin light chains of beef and pig heart.