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.

    82/210 (page 60)
    observations of Embden and Knoop that any doubt of Neumeister’s view was entertained. In experiments designed to show the fate of proteoses and peptones when brought into contact with the intestinal wall Embden and Knoop were able to show the presence in the blood of substances having the properties of pro- teoses and peptones. They held that the mucous mem- brane of the intestine neither synthesized these sub- stances to a larger molecule, as for example to a coagu- lable protein, nor were they hydrolyzed to the amino acid stage but, on the contrary, absorption took place directly. The results of Embden and Knoop were con- firmed by some observers and discredited by others. Schumm for example was always unable to find a trace of proteose in the blood both under normal and ab- normal conditions of health. Abderhalden and his co- workers maintained that the substances giving reactions for proteoses and peptones were present because of imperfect methods employed in the separa- tion of the coagulable protein from the blood. It has been pointed out by others, however, that there is a possibility of the presence in the blood of a protein naturally non-coagulable which would still give the reaction—the biuret test-—significant under the experi- mental conditions for the presence of proteose or pep- tone. Zanetti described such a protein in the blood and found that it belonged to the group of mucoids. Among others, Howell believes in the existence in the blood of a protein possessing some of the character- istics of the proteoses and peptones, for example, non-