104 



Iodine Complex of Thyreoglobulin 



The mass was then ground to a coarse powder and fat removed by ether in 

 the cold. The remaining dry mass was then finely powdered. Duplicate 

 determinations on this gave 0.243 and 0.250 per cent iodine. 



Thyreoglobulin. This was prepared as previously described. 15 Dupli- 

 cate determinations on this gave 0.462 and 0.468 per cent iodine. 



lodothyrin (a) was prepared by the usual Baumann process from the above 

 thyreoglobulin. The extraction with 95 per cent alcohol of the melanoidin 

 precipitate was made in a continuous hot extractor. Duplicate determina- 

 tions gave 5.81 and 5.85 per cent iodine. 



lodothyrin (6) was obtained in the same way from the melanoidin precipi- 

 tate which separated in the complete hydrolysis of some of the same thyreo- 

 globulin by 30-35 per cent sulphuric acid. This on analysis gave 7.51 per 

 cent iodine. 



lodothyrin (c) was obtained from 40 grams of the same globulin by hydroly- 

 sis for three days at room temperature and for twenty-four hours at boil- 

 ing temperature with 20-25 per cent phosphoric acid. Phosphoric acid 

 was used as it was thought that possibly the oxidative action of sulphuric 

 acid might have an injurious effect. This amount of globulin yielded 3.30 

 grams of melanoidin, containing 1.75 per cent iodine. The iodothyrin 

 extracted from this represented 24 per cent of the weight and contained 4.44- 

 4.46 per cent iodine. Thus only 61 per cent of the iodine in the melanoidin 

 fraction was recovered in the alcohol extract. 



Metaprotein (A 4 ). The nitrate from the melanoidin fraction above was 

 neutralized with NaOH and the metaprotein separated and dried over sul- 

 phuric acid in a vacuum desiccator. This weighed 1 .62 grams and contained 

 1.51-1.53 per cent iodine. 



Primary albumose (A 6 ). The filtrate from above was half saturated with 

 zinc sulphate after slightly acidifying with sulphuric acid. The precipitate 

 obtained was dialyzed until free from sulphate. In this fraction there were 

 recovered 3.1 grams containing 0.22-0.225 per cent iodine. 



Secondary albumose (A 6 ). Obtained from the filtrate from above by com- 

 plete saturation with zinc sulphate. The precipitate after dialyzing as 

 above yielded 4 grams dry substance containing 0.069 per cent iodine. 



The table (I) below gives a summary of the distribution of iodine in the 

 different fractions above. 



TABLE I. 



15 This Journal, ix, p. 121, 1911. 



