The physiology of the amino acids / by Frank P. Underhill.

  • Frank Pell Underhill
Date:
1915
Catalogue details

Licence: In copyright

Credit: The physiology of the amino acids / by Frank P. Underhill. Source: Wellcome Collection.

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    Occurrence and Characteristics of Different Classes of Proteins A. Simple Proteins Albumins are simple proteins that are soluble in pure water and are coagulable by heat. Globulins, on the other hand, are insoluble in pure water but are readily soluble in dilute salt solutions. Albumins and globulins are generally found together in nature occurring, for example, in large quantity in the blood serum, wdiite of egg, in the substance of cells in gen- eral, and in various seeds. Egg white may be divided into two parts by dialysis against distilled water— the globulin being precipitated owing to the diffusion of the salts from the solution which originally were present in quantity sufficient to hold the globulin in solution. Glutelins are simple proteins insoluble in all neu- tral solvents but easily soluble in very dilute acids and alkalies. Alcohol-Soluble Proteins are simple proteins readily soluble in relatively strong alcohol (70 to 80 per cent), but are insoluble in water, absolute alco- hol and other neutral solvents. These two groups of proteins occur together as constituents of the cereal grains. Glutenin and Gliadin, respectively, from wheat, are the best known examples of these two groups. They constitute the gluten of flour. The elasticity and strength of the gluten, and therefore the
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