title: Purification, partial characterization and peptide sequences of vitellogenin from a reptile, the tuatara (Sphenodon punctatus).
abstract: Vitellogenin (Vg), a major precursor to egg yolk proteins, was purified from plasma of an estradiol-treated female tuatara (Sphenodon punctatus) by MgCl2-EDTA precipitation and DEAE-cellulose chromatography. The amino acid composition of tuatara Vg is similar to that of other vertebtate Vgs and contains a large proportion of serine (13.7 mol/100 mol of total amino acid). The amino acid sequences of the N-terminus of mature Vg (33 residues) and of several trypsin- and CNBr-generated peptides were determined. Six peptide sequences obtained from tuatara Vg could be aligned with Vg sequences from other vertebrates. Reduced and non-reduced forms of tuatara Vg have the same apparent molecular mass (approximately 218 kDa) when resolved by SDS-PAGE, indicating that inter-chain disulfide bonds are not a feature of the molecule in this species. Western blot analysis with anti-tuatara Vg antiserum indicated that at least some epitopes are shared among Vgs of turtle, alligator and tuatara.
authors.affiliation: Biochemistry and Genetics Research Unit, School of Biological Sciences, Victoria University of Wellington, New Zealand. mabrown@unixg.ubc.ca
authors.forename: M A
authors.initials: MA
authors.lastname: Brown
authors.forename: A
authors.initials: A
authors.lastname: Carne
authors.forename: G K
authors.initials: GK
authors.lastname: Chambers
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D015153:Blotting, Western; D011232:Chemical Precipitation; D002848:Chromatography, DEAE-Cellulose; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D015636:Magnesium Chloride; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D012104:Reptiles; D017421:Sequence Analysis; D013045:Species Specificity; D014357:Trypsin; D014819:Vitellogenins / Q000097:blood* / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D014819:Vitellogenins; D015636:Magnesium Chloride; D004958:Estradiol; D014357:Trypsin; D003488:Cyanogen Bromide