Proteins of the cotton seed.

Abstract

By extracting finely ground cottonseed kernels (hull-free) with benzene (C₆H₆) nearly all of the fatty and resinous substances and much of the coloring material is eliminated. For this purpose benzene is far superior to ether. Such a thorough removal of the above substances from the flour greatly facilitates a satisfactory subsequent extraction of the proteins by different solvents. The high percentage of nitrogen extracted by sodium chloride solution (Table I) is doubtless due to the method of preparation of the flour.

We were able to separate from the salt extract two globulins. Of these one can be precipitated directly at 0.4 to 0.5 of saturation with ammonium sulfate. The other flocculates at a saturation of 0.7 to 0.8, but only after it is diluted with water so that the ratio of the final volume to the weight of the original cottonseed flour extracted is as 50:1.

A fraction having a relatively low nitrogen content, but containing a constant and very high ash percentage was obtained from the salt extract by coagulation; the composition of this preparation points to a nucleic acid. The examination of this product is under way and the results will be published later.

The globulins were prepared by reprecipitation with ammonium sulfate followed by dialysis. The identification of glutelin and a nucleo protein present in the meal, and also the chemical analyses and determination of certain physical constants of the different protein fractions are under way.