Kinetics of Haemoglobin in Red Blood Corpuscle 



that the layer of concentrated haemoglobin is bounded by a membrane 

 of two different permeabilities, indicated by 1/X = 2-0 and 3-0 respec- 

 tively. The observed results are fitted by assuming that 1/X = 2-6. 

 1/X is defined as equal to DJbx ■£■ D 2 \b 2 



where D x = diffusion coefficient of interior of corpuscle to CO 

 D 2 — diffusion coefficient of corpuscle membrane to CO 

 2b x = thickness of interior of corpuscle 

 b 2 = thickness of corpuscle membrane. 



bj for sheep red blood corpuscles may be taken as 7 x 10- 5 cm. 



The value of b 2 is uncertain, but according to various biophysical 

 estimates is of the order of 10 -6 cms. 



On this basis it follows that DJ7xlO~ s -f- D 2 /10~ 6 = 2-6 whence 

 DJD 1 = -0055 D x 



The value of D x is not known, but is probably appreciably less than 

 that for pure water. According to A. S. Krogh 20 , the diffusion constant 

 of D 2 through a 20 per cent gelatine gel = about 80 per cent of D Q2 

 for water. We have provisionally assumed a similar value for D x 

 inside the corpuscle. It is hoped later to test the validity of this postu- 

 late by direct determinations of D Q2 and D co in 36 per cent solution 

 of haemoglobin. The value of D 2 , if our assumptions are correct, 

 is thus not more that 1/200 the value of D co in water. 



Figure 6 shows the calculated relations between the half time of the 

 reaction 6 and 1/X (defined as above) for three reactions of widely 

 varying rate, viz. k' = 3-3 (corresponding to 2 + Hb-> 2 Hb, with 

 2 measured in partial pressures of dissolved gas in mm Hg), 



040 



- OJO, 



Figure 6. Relation between 

 calculated value of half time 

 of saturation, 9, and 1/X, for 

 three reactions of widely vary- 

 ing rate. 





^010 



10 



S\ 



k' = 0-33 (corresponding to CO + Hb->COHb) and k' = 0-033. 

 There is an almost linear relation in all three cases : the slope of the 

 line is practically independent of the value of k', and is approximately 



79 



