Haemoglobins of the Shark, Heterodontus portusjacksoni

Abstract

The haemoglobins of the Port Jackson shark, H. portusjacksoni, were resolved by cation-exchange chromatography of their carboxymethylated forms into two fractions, Hb-I and Hb-II, which were present in approximately equal proportions. A third, non-haem, acidic protein component, representing 5 % of the total protein, was also resolved. This protein is apparently of high molecular weight and is present in different polymorphic forms. The haemoglobins of the shark are subject to rapid aggregation, by disulphide bond formation, following lysis of the red cells. The aggregation is reversed by treatment with thiols, and prevented by combination of the two to four 'reactive' thiol groups with iodoacetate or other thiol-blocking reagents. The molecular weights of the haemoglobins are approximately 61 000, suggesting a tetrameric molecule.