title: Isolation and characterization of a new 40-kilodalton protein from bovine cardiac muscle.
abstract: A new protein having a subunit weight of 40,000 has been purified from myosin-extracted bovine cardiac myofibrils. Its amino acid composition and isoelectric point are distinct from actin, eu-actinin, and a variety of sarcoplasmic proteins of similar size. Affinity-purified antibodies made to this protein only react with a single 40-kDa protein band from cardiac myofibrils on immunoblots. The anti-40-kDa protein also shows cross-reactivities with cardiac myofibrils from rabbits, rats, and chickens. Immunofluorescence studies demonstrate that the 40-kDa protein is localized at the Z-bands of cardiac myofibrils and at the intercalated discs. The antibody did not react with skeletal muscle myofibrils by immunofluorescence or immunoblotting. It appears that the 40-kDa protein may play a role in the strong attachments between adjacent myofibrils in cardiac muscle.
mesh_terms: D000185:Actinin / Q000032:analysis; D000199:Actins / Q000032:analysis; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000906:Antibodies; D002417:Cattle; D002645:Chickens; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D007526:Isoelectric Point; D008970:Molecular Weight; D009132:Muscles / Q000032:analysis; D009206:Myocardium / Q000032:analysis*; D009218:Myosins / Q000378:metabolism; D011506:Proteins / Q000032:analysis / Q000302:isolation & purification*; D011817:Rabbits; D051381:Rats; D013045:Species Specificity
chemical_list: D000199:Actins; D000596:Amino Acids; D000906:Antibodies; D011506:Proteins; D000185:Actinin; D009218:Myosins