I 



14 THE PROTEINS OF THE WHEAT KERNEL. 



Osborne & Harris, 1 in a study of the different forms of binding of nitrogen 

 in proteins, found that leucosin of wheat yielded 1.16 per cent of nitrogen 

 as ammonia and 3 50 per cent of nitrogen in basic compounds, precipitable 

 by phosphotungstic acid ; that the globulin yielded 1.42 percent of nitrogen 

 as ammonia and 6.83 percent of basic nitrogen; that gliadin yielded 4.3 

 per cent of nitrogen as ammonia and 1.09 per cent of basic nitrogen, and 

 that glutenin yielded 3.31 per cent of nitrogen as ammonia and 2.05 per cent 

 of basic nitrogen. They also found 2 that, while none of the wheat proteins 

 yielded any furfurol on distillation with hydrochloric acid, glutenin gave a 

 moderately strong, gliadin a strong, and leucosin a very strong reaction with 

 the Molisch test. This test is commonly regarded as giving evidence of a 

 carbohydrate complex in the protein molecule, but they decided that other 

 evidence is necessary before such a conclusion is justified. 



Osborne & Harris 3 found the specific rotation of gliadin dissolved in 

 alcohol of 80 per cent by volume to be 91.9 and 92.5. In comparing 

 the tryptophane reaction of many proteins these same authors found 4 that 

 the globulin of wheat gave only a slight reaction, gliadin and glutenin one 

 of medium intensity, and leucosin the strongest reaction of all the proteins 

 examined, thus indicating the relative amounts of tryptophane or indol- 

 amino-propionic acid which these proteins yield on decomposition with acid. 



Kutscher 5 determined the amount of tyrosine and glutaminic acid yielded 

 by the proteins of wheat gluten when decomposed by boiling with sulphuric 

 acid. In glutenin he found 2.75, in gluten-fibrin 4.43, in gliadin 2.09, and 

 in mucedin 2.35 per cent of tyrosine ; in glutenin 9, in gluten-fibrin 13.07, 

 in gliadin 18.54, an d * n mucedin 19.81 per cent of glutaminic acid. 



Naysmith 6 found that gluten contained 0.12 per cent of phosphorus. 

 Gliadin extracted by 70 per cent alcohol from gluten and separated by 

 evaporating to dryness contained 0.29 per cent of phosphorus, but when 

 precipitated from the alcoholic extract by dilute sodium chloride solution it 

 contained only 0.19 per cent. 



Glutenin also contained 0.21 per cent of phosphorus. Both these proteins 

 contained iron. Phosphorus and iron are not constituents of the molecules 

 of these proteins, but are derived from the cell nuclei. 



Although gliadin and glutenin contain phosphorus, they are not nucleo- 

 proteids. Naysmith also concluded that no ferment action occurred in the 

 formation of gluten. 



1 Osborne & Harris, Journal American Chemical Society, 1903, xxv, p. 323. 

 2 Ibid., p. 474. 

 3 Ibid., p. 844. 

 4 Ibid., p. 854. 



5 Kutscher, Zeitschrift fur physiologische Chemie, 1903, xxxvin, p. in. 



6 Naysmith, Transactions of the Canadian Institute, 1903, vn. 



