title: Characterization and partial amino acid sequence of a low molecular weight surfactant protein.
abstract: Chloroform:methanol (2:1) extracts of bovine surfactant were subjected to LH-20 Sephadex chromatography in order to isolate a 6,000-dalton surfactant protein. The 6,000-dalton protein eluted in the void volume and was shown to be homogeneous by protein sequencing, although SDS gel electrophoresis revealed bands of 6, 14, and 18 kDa. The N-terminal sequence obtained was very hydrophobic, as was the amino acid composition of the 6,000-dalton protein. An antiserum raised against the low molecular weight protein fraction from TA surfactant recognized the 6,000-dalton bovine and human proteins in addition to protein bands at 14,000 and 18,000 daltons. These bands appear to be aggregates of the 6,000-dalton protein. No cross-reactivity of the 6,000-dalton protein antiserum could be demonstrated with the 35,000-dalton surfactant-associated protein. These studies strongly suggest that the 35,000- and 6,000-dalton surfactant proteins do not have a precursor-product relationship.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D002417:Cattle; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007120:Immunochemistry; D008970:Molecular Weight; D011510:Proteolipids / Q000032:analysis*; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000032:analysis*
chemical_list: D000596:Amino Acids; D011510:Proteolipids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants