title: Characterization of the constituent polypeptides of the extracellular hemoglobin from Lumbricus terrestris: heterogeneity and discovery of a new linker chain L4.
abstract: The extracellular hemoglobin of Lumbricus terrestris comprises four oxygen binding chains, a, b, c, d, and three linker chains L1, L2, L3 as major components. A stoichiometry of the whole molecule has been proposed on the basis of these chains, with a total number of 216 chains: forty-eight chains of each oxygen binding chain and eight molecules of each linker chain. We have isolated additional minor components by HPLC and two-dimensional gel electrophoresis. The following biochemical characterizations have been made. (i) All components so far reported, the heme-containing chains a, b, c, d, and linker chains L1, L2, L3 and a new minor polypeptide, L4, were mapped on a two-dimensional gel. Their estimated isoelectric points were between 4.7 and 5.9. (ii) The sequences of several peptides including the unique N-terminal peptide from linker L4 show that it can be considered as a duplicated gene product with a similar mass. (iii) Chain d2 was isolated and found to correspond to the minor chain previously pointed out by Shishikura et al. (J. Biol. Chem. 262 (1987) 3123-3131). (iv) The major chain d1 has serine at position 7 from the N-terminus. This is not consistent with previously reported glycine (Shishikura et al., J. Biol. Chem. 262 (1987) 3123-3131).
authors.affiliation: Department of Biochemistry, Kawasaki Medical School, Okayama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fushitani
authors.forename: K
authors.initials: K
authors.lastname: Higashiyama
authors.forename: M
authors.initials: M
authors.lastname: Asao
authors.forename: K
authors.initials: K
authors.lastname: Hosokawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D006454:Hemoglobins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009835:Oligochaeta / Q000737:chemistry*; D010108:Oxyhemoglobins / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D014357:Trypsin
chemical_list: D006454:Hemoglobins; D046911:Macromolecular Substances; D010108:Oxyhemoglobins; D010446:Peptide Fragments; D014357:Trypsin