title: Subunits of the extracellular hemoglobin of Arenicola marina.
abstract: The molecular weight of the extracellular hemoglobin of Arenicola marina determined by equilibrium sedimentation is 3.74 +/- 0.12 . 10(6). Its iron content is 0.244 +/- 0.005 wt.% corresponding to a minimum molcular weight of 22 900 +/- 500. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed that the hemoglobin dissociated into three subunits: 14 000 (subunit 1), 31 000 (subunit 2) and 49 000 (subunit 3); in the presence of 2-mercaptoethanol four subunits were observed, 14 000 (subunit I), 16 000 (subunit II), 31 000 (subunit III), and 35 000 (subunit IV). Two-dimensional electrophoresis showed that subunit 1 produced subunit I, and subunits 2 and 3 produced subunits I, II and variable amounts of subunits III and IV. Gel filtration of reduced and alkylated A. marina hemoglobin in 6 M guanidinium hydrochloride suggests that the molecular weight of subunits I and II is 17 500 +/- 1000. A. marina hemoglobin appears to consist of at least 5--7 polypeptide chains. It is proposed that some of the polypeptide chains can associate to form dimers (subunits 2, III, IV) or trimers (subunit 3).
mesh_terms: D000845:Annelida / Q000032:analysis*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006146:Guanidines; D006454:Hemoglobins / Q000032:analysis*; D006851:Hydrochloric Acid; D007501:Iron / Q000097:blood; D046911:Macromolecular Substances; D008623:Mercaptoethanol; D008706:Methemoglobin / Q000031:analogs & derivatives / Q000032:analysis; D008970:Molecular Weight; D009570:Nitriles / Q000032:analysis; D013057:Spectrum Analysis
chemical_list: D006146:Guanidines; D006454:Hemoglobins; D046911:Macromolecular Substances; D009570:Nitriles; D008623:Mercaptoethanol; D008706:Methemoglobin; D007501:Iron; D006851:Hydrochloric Acid