title: An electrophoretic variant of a human fibroblast protein with characteristics of smooth muscle tropomyosin.
abstract: A charge variant of a protein (Tm: 3; molecular weight approximately 35,000) that co-migrates with human smooth muscle tropomyosin has been found in whole cell extracts from the fibroblasts of a father and his son. The variant protein co-purifies with Tm: 3, shifts with it to a higher apparent molecular weight on sodium dodecyl sulfate/polyacrylamide gel electrophoresis in the presence of 4 M-urea, is a component of the microfilaments, and has a peptide cleavage pattern identical to that of Tm: 3 and smooth muscle tropomyosin. The results indicate that Tm: 3 and the variant (Tm: 3.1) are smooth muscle tropomyosin, suggesting that normal human fibroblasts synthesize at least two tropomyosins (Tm:3 and the non-muscle tropomyosin Tm:4, molecular weight approximately 30,000) and that they are the products of separate genes.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000032:analysis*; D006801:Humans; D008297:Male; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000032:analysis; D011506:Proteins / Q000032:analysis* / Q000235:genetics; D014335:Tropomyosin / Q000032:analysis*
chemical_list: D000596:Amino Acids; D011506:Proteins; D014335:Tropomyosin