title: Oxygen equilibrium and subunit aggregation of a holothurian hemoglobin.
abstract: The hemoglobin of the sea cucumber Cucumaria miniata Brandt has a mol. wt of about 36000 in the oxy- form with a s20,w equal to 2.9 and a subunit molecular weight of 18000 by sodium dodecylsulfate gel electrophoresis. This pigment aggregates when deoxygenated to an oligomer with a s20,w equal to 4.7, an aggregation which is reversible upon subsequent oxygenation. The hemoglobin shows a sigmoid binding equilibrium with "n" equal to 1.8 and a decrease in oxygen affinity with an increase in pigment concentration. This  hemoglobin is compared with other hemoglobins showing oxygenation-linked subunit aggregation.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002850:Chromatography, Gel; D004447:Echinodermata / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D006454:Hemoglobins; D046911:Macromolecular Substances; D008970:Molecular Weight; D010100:Oxygen; D011485:Protein Binding; D014461:Ultracentrifugation
chemical_list: D006454:Hemoglobins; D046911:Macromolecular Substances; D010100:Oxygen