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

  • Underhill, Frank P. (Frank Pell), 1877-1932.
Date:
1915
Catalogue details

Licence: In copyright

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

    121/210 (page 99)
    THE FURTHER FATE OF AMINO ACIDS It is well recognized that a large part of the amino acids of the food is eliminated from the body in the form of urea, carbon dioxide, and water. The various amino acids presumably undergo a variety of chemical changes previous to their excretion as the simple pro- ducts mentioned above. Also the ease with which these transformations take place is different for the indi- vidual amino acids. The steps leading to the ultimate fate of some are quite clear, of others it is very ob- scure or entirely unknown. The unlike ease of trans- formation of amino acids into urea has been shown by intravenous injection. Thus glycocoll and leucine yield urea more or less completely whereas alanine, cystine, aspartic and glutamic acids are not readily catabolized. In general the first step in the metabolism of amino acids is that of oxidative deamination—a splitting off of ammonia with an accompanying oxidation. For any straight chain amino acid the reaction occurring may be represented as follows: R.CH2.CH.NH2.COOH + O = R.CH2.COOH + COa + NH,