Electrophoretic Differentiation ofMyofibrillar Proteins inthePig

decreased thenumberofmajorelectrophoretically distinct components ofthefresh myosinof bothmuscles tofour. 5.Although there wasalso somesimplification ofthepatterns after freeze-drying thegreater susceptibility ofthemyosinfromlongissimus dorsi wasstill evident. 6.Thetypical pattern forfreshly prepared tropomyosin in8Mureadiffered inthetwomuscles: ineachcaseitwasmorecomplex thanthatofthe corresponding myosins. 7.Thepattern oftropomyosin fromneither longissimus dorsi norpsoaswasaltered significantly after freeze-drying. 8.Electrophoretogramsofpiglongissimus dorsi tropomyosin in8M-urea differed fromthoseof longissimus dorsi tropomyosin fromsheep, oxandrabbit. 9.Extraction ofthe tropomyosins in8m-urea and2%fl-mercaptoethanol simplified theelectrophoretic pattern totwomajorcomponents withsamples frompig, sheepandox,andtoone majorcomponent withsamples fromrabbit. 10.Itwasconcluded thatclassification ofskeletal muscles as'red' or'white' isinsufficient toaccountforthe degree offunctional specialization whichtheelectrophoretograms suggest.