ioo8 



CARBOHYDRATE METABOLISM 



[PT. Ill 



curve the conclusion might be drawn that ovomucoid is a more 

 labile element in the raw materials of the embryo than has usually- 

 been supposed. The work of Anson & Mirsky on another conjugated 

 protein, haemoglobin, showed the ease with which the prosthetic 

 group can be detached from and re-attached to the protein part of 

 the molecule. 



Komori gave other figures for the amounts of ovomucoid present 

 during development, but expressed them as grams per cent, of dry 

 weight of albumen, so that, although we know the rate at which 

 the albumen is drying up, we cannot calculate his figures in milli- 

 grams absolute per egg because we do not know the relative weights 

 of yolk and white. Sakuragi's figures for the same fraction are not 

 valuable, being few in number 

 and obtained by the use of 

 doubtful precipitations prior to 

 total hydrolysis and estimation 

 by copper reduction. The only 

 extensive work on the physiology ' 

 of ovomucoid is that of By waters, 

 who found that, between the ist 

 and 1 8th day of development, 

 the ratio of uncoagulable pro- 

 tein nitrogen to coagulable pro- 

 tein nitrogen in the egg-white 

 was steady at 0-136, and therefore concluded that there was no 

 preferential absorption of ovomucoid or ovoalbumen. This does not 

 at first sight agree with the curve shown in Fig. 269. Two hypotheses 

 are open: (i) that the curve for ovomucoid glucose calculated by 

 difference does not accurately represent the ovomucoid glucose, or 

 (2) that at varying times in development the amount of glucose 

 combined in the ovomucoid molecule varies considerably. Both 

 these seem possible. Bywaters found no change in the amount of 

 sugar in the uncoagulable protein between the i st and the 1 8th day ; 

 it remained constant at about 27 per cent., and, as the ratio of 

 the two expressed as grams per 100 gm. egg-white was more or less 

 constant (see Fig. 272 and Table 128), he considered that the carbo- 

 hydrate radicle of ovomucoid was not split oflf before absorption. His 

 methods are, however, not free from criticism, for he used the original 

 method of Pavy without modification, and only hydrolysed the ovo- 



Fig. 272. 



