Characterization of hemoglobin from the backswimmer Buenoa margaritacea (Hemiptera: Notonectidae) reveals high electrophoretic heterogeneity

Backswimmers (Notonectidae) are one of the three families of insects which contain species known to make hemoglobin. In backswimmers the hemoglobin allows the insect to maintain a prolonged neutral buoyancy during its dive. Sephadex G-200 column chromatography, SDS-polyacrylamide gel electrophoresis and HPLC demonstrate a molecular weight for the monomeric hemoglobin og Buenoa margaritacea of 15,000-19,000 Da. u.v.-visible spectra at eight hemoglobin derivatives (Fe²⁺:deoxy, O₂, CO, NO; Fe³⁺:H₂O, OH^-, CN^-, imidazole) are given. Native gel electrophoresis of the cyanomet form shows nine bands, while isoelectric focusing shows 12. Bands isolated from preparative IEF gels form multiple bands when rerun, indicative of a change in aggregation status after isolation. Interactions among various hemoglobin components are seen using 2-dimensional "titration" electrophoresis.