Haemoglobins of Ascaris lumbricoides xar suis 



under all conditions the reaction occurred too rapidly for measurement. 

 With perienteric fluid haemoglobin at 3°C, /?H 6, t 50 is 10-3 sec, 

 compared with 3,000 sec for the oxygen dissociation. 



640 620 600 580 560 540 520 500 480 

 m ii 



Figure 2. Absorption spectra of Ascaris 

 body-wall haemoglobin (A), oxyhemo- 

 globin (B) and CO -haemoglobin (C). 



2-303 

 c.d. 



log j 



where c = haematin concentration as g. 

 mols./ml. 

 d = thickness of cell in centi- 

 metres. 



J and I = Intensities of incident and 

 transmitted light respectively. 



The impossibility of obtaining complete deoxygenation of the 

 haemoglobins in the absence of a reducing agent prevented the use 

 of a direct method for determining the oxygen equihbrium curves. 

 R. Hill 11 has used haemoglobins of known oxygen affinities to 

 measure the quantities of oxygen evolved when isolated chloroplasts 

 were illuminated. The tensions of oxygen attained were low and a 

 haemoglobin of high oxygen affinity, ox muscle haemoglobin, was 

 used. Aqueous leaf extracts, shown by Hill to promote oxygen 

 evolution from isolated chloroplasts, were found to bring about a 

 slow deoxygenation of the Ascaris oxyhaemoglobins when they are 

 incubated together in a vacuum. If chloroplasts were then added to 

 the deoxygenated haemoglobin and illuminated a rapid and complete 

 reoxygenation of the haemoglobin occurred. The progress of the 

 reoxygenation was measured and compared with that of ox muscle 



299 



