title: Analysis of variant forms of porcine surfactant polypeptide-C by nano-electrospray mass spectrometry.
abstract: Electrospray (ES) mass spectrometry has been used to analyse preparations of porcine pulmonary surfactant polypeptide-C (SP-C). A number of variant forms of the native 35-residue dipalmitoylated peptide were detected including (a) C-terminally methylated SP-C, (b) C-terminally methylated and methionine oxidized SP-C, (c) N-terminally truncated, C-terminally methylated and methionine oxidized SP-c, (d) C-terminally elongated, C-terminally methylated and methionine oxidized SP-C, and (e) tripalmitoylated, C-terminally methylated and methionine oxidized SP-C. C-terminal methylation and methionine oxidation are probably a consequence of the sample handling procedure. The occurrence of the C-terminally elongated form of SP-C has implications for the in vivo processing of proSP-C and the Tandem mass spectrometry (MS/MS) was used to confirm the amino acid sequence of SP-C and the presence of palmitoyl groups covalently linked to the peptide. Some of the structures of the variant forms of SP-C were determined by MS/MS.
authors.affiliation: Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: W J
authors.initials: WJ
authors.lastname: Griffiths
authors.forename: M
authors.initials: M
authors.lastname: Gustafsson
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Curstedt
authors.forename: J
authors.initials: J
authors.lastname: Sjövall
authors.forename: J
authors.initials: J
authors.lastname: Johansson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002942:Circular Dichroism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D011510:Proteolipids / Q000032:analysis*; D011663:Pulmonary Surfactants / Q000032:analysis*; D013552:Swine
chemical_list: D010446:Peptide Fragments; D011510:Proteolipids; D011663:Pulmonary Surfactants