title: Lung surfactant protein SP-C from human, bovine, and canine sources contains palmityl cysteine thioester linkages.
abstract: Lung surfactant is a complex mixture of lipids and proteins that coats the alveoli to reduce surface tension and prevent airspace collapse. One of the principal protein constituents, surfactant protein C (SP-C), has been characterized following isolation from human, canine, and bovine sources. In each species, this highly hydrophobic protein is composed of 33-35 amino acids, the differences being due to NH2-terminal heterogeneity. A COOH-terminal leucine is conserved throughout. The cysteines in each species were found by fast atom bombardment mass spectrometry to be present as thioesters of palmitic acid. Acylation of recombinant SP-C with palmityl coenzyme A, followed by characterization before and after release of the acyl group with 1,4-dithiothreitol, provided corroborating evidence for the native structure.
authors.affiliation: Department of Protein Chemistry, Genentech, South San Francisco 94080.
authors.forename: J T
authors.initials: JT
authors.lastname: Stults
authors.forename: P R
authors.initials: PR
authors.lastname: Griffin
authors.forename: D D
authors.initials: DD
authors.lastname: Lesikar
authors.forename: A
authors.initials: A
authors.lastname: Naidu
authors.forename: B
authors.initials: B
authors.lastname: Moffat
authors.forename: B J
authors.initials: BJ
authors.lastname: Benson
mesh_terms: D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000378:metabolism*; D004229:Dithiothreitol / Q000494:pharmacology; D004285:Dogs; D006801:Humans; D008969:Molecular Sequence Data; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D011510:Proteolipids / Q000737:chemistry*; D011663:Pulmonary Surfactants / Q000737:chemistry*; D013057:Spectrum Analysis; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D010169:Palmitic Acids; D011510:Proteolipids; D011663:Pulmonary Surfactants; D013438:Sulfhydryl Compounds; D019308:Palmitic Acid; D003545:Cysteine; D004229:Dithiothreitol