A study of the proteids of the corn or maize kernel.

  • Russell Henry Chittenden
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: A study of the proteids of the corn or maize kernel. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    slightly higher percentages of nitrogen in the products A3 and A3, From the data here offered there is no positive evidence as to whether A1 is an alteration-product of the original globulin, or whether it simply represents a small impurity. The former view is certainly the more plausible one, however, especially when it is remembered that this globulin had been dissolved in a salt solu- tion and filtered two or three times previously. Again, it is to be noticed in comparing the two soluble products A3 and A3, that the body containing the lower percentage of nitrogen contains the higher percentage of carbon ; and further, that in both products the percentage of nitrogen is by this treatment raised so as to correspond closely with the nitrogen content of pure phyto- vitellin. In view of these results a portion of corn globulin was next separated into a number of fractions by the solvent action of various strengths of salt solution, and the several fractions studied, especially with reference to their composition and heat-coagula- tion points. The globulin (Preparation E) was made from 5 kilos, of freshly ground corn by direct extraction with an abundance of 10-per cent, solution of sodium chloride, the proteids precipitated by saturation of the filtered solution with ammonium sulphate, this precipitate dissolved in water and salt solution, and the filtered fluid dialysed in running water for one week until the globulin had separated. The entire quantity of globulin, about 10 grams, was then treated directly with one litre of 0.25-per cent, solution of sodium chloride at the temperature of the room and kept in agitation for about 3 hours. The residue was then filtered off and extracted again with one litre of salt solution of the same strength, the solution being kept in contact with the globulin for about 18 hours. This was likewise filtered off and the residue again extracted with two litres of 0.25-per cent, salt solution. A portion of the com- bined extract obtained in this manner, on being heated, grew slightly turbid at 540 ; this turbidity was still slight at 63°, but at 710 a flocculent coagulum appeared. No funher coagulum appeared until the solution was boiled, and then only a slight one. The filtrate from this precipitate gave a faint reaction with acetic acid and potassium ferrocyanide. These united extracts were then placed in dialysers and dialysed in running water until the
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