The haemoglobins of Ascaris Lumbricoides

The occurrence of distinct haemoglobins in the perienteric fluid and body wall of Ascaris is confirmed and methods described for the extraction and partial purification of the pigments. The absorption spectra of the haemoglobins and their principal derivatives were determined. Both haemoglobins possess a remarkable resistance to deoxygenation. This is due principally to a low deoxygenation velocity. In presence of Na2S2O4 at 20.5°C, pH 6, t50 for the deoxygenation of the perienteric fluid haemoglobin is 150 sec. compared with 0.008 sec. for sheep haemoglobin (Hartridge & Houghton 1923). With the body-wall haemoglobin the reaction is more rapid; t50 at pH 6, 3°C, is 80 ± 10 sec. The deoxygenation reaction is accurately unimolecular and is independent of the con­centration of the reducing agent. With perienteric fluid haemoglobin the temperature coefficient of the reaction is 5 and the velocity is increased with increase of pH between 5 and 9. The velocity of conversion of the oxyhaemoglobins to methaemoglobin in presence of K3Fe(CN )6 was measured. In vacuo t50 is the same as for the deoxygenation reaction but diverges from unimolecular characteristics beyond half completion. Although the velocity is independent of the ferricyanide concentration, a measurable back reaction with O2 occurs. CO dissociates from both haemoglobins more rapidly than oxygen; 300 times more rapidly with perienteric fluid haemoglobin at pH 6, 3°C. When Ascaris is kept under anaerobic conditions the body-wall haemoglobin becomes deoxygenated but no change could be detected in the perienteric fluid haemoglobin.