H. E. DAVENPORT 



contains 3-3 x 10 ~ 5 M haematin, representing as haemoglobin 2 per 

 cent of the total protein. Individuals having higher or lower con- 

 centrations of haemoglobin in the perienteric fluid exhibit a parallel 

 variation in the body wall haemoglobin concentration. 



For a study of the properties of the haemoglobins they were 

 extracted and partially purified. From the perienteric fluid, by 

 fractionation with (NHJaSO^ preparations containing 2-5 x 10 ~ 4 M 

 haematin were obtained. Haemoglobin represented 12 per cent of 

 the dry weight. Similar preparations were obtained from the body 

 wall after the haemoglobin had first been extracted by soaking in 

 distilled water. 



In these concentrated solutions the two haemoglobins retained the 

 characteristic difference in their absorption band positions but the 

 spectra differed from mammalian oxyhaemoglobins in two important 

 respects. The absorption bands are more diffuse and the density of 

 the fi band is greater than that of the a band. A similar type of 

 spectrum has been reported by D. Keilin and Y. L. Wang 3 for the 

 oxyhaemoglobin they extracted from root nodules of leguminous plants. 



In order to confirm that the pigments are true oxyhaemoglobins it 

 was necessary to show that they possess the property of reversible 

 oxygenation. Both however were found to have a remarkable 

 resistance to deoxygenation when solutions were equilibrated against 

 a frequently renewed vacuum. After equilibration for 3 hours at 

 20 °C the body wall haemoglobin was 50 per cent deoxygenated but 

 only slight evidence of deoxygenation could be observed in the 

 perienteric fluid haemoglobin. On treating the solutions with sodium 

 hyposulphite the two bands disappear and are replaced by a single 

 band with the maximum at 555m[x. What is remarkable is that the 

 change occurs slowly in contrast to the apparently instantaneous 

 deoxygenation of other oxyhaemoglobins when they are treated with 

 this reagent. 



The kinetics of the dissociation of oxygen from haemoglobin was 

 first investigated by H. H. Hartridge and F. J. W. Roughton 4 using 

 sheep haemoglobin. The measurements have been extended by G. A. 

 Millikan 5 ' 6 to other vertebrate haemoglobins and by K. Salomon 7 

 to two invertebrate haemoglobins. In every case the reaction was so 

 rapid that the rapid flow technique devised by Hartridge and Roughton 

 was necessary for measurements to be made. With the Ascaris 

 haemoglobins, on the other hand, the slowness of the reaction made 

 possible the use of a simple static method. 



In presence of Na 2 S 2 4 in vacuo the reaction follows a strictly 

 unimolecular course with both haemoglobins and its velocity is 

 independent of the concentration of the reducing agent. By the 



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