The excretion of amino acids by the human. A quantitative study with ion-exchange chromatography

Publisher Website
Google Scholar
Abstract
By ion-exchange chromato-graphy daily excretions of amino acids and midday plasma levels were determined for a number of healthy adults and for patients with amino aciduria. The normal subjects and each of the patients studied showed distinctive patterns of amino acid excretion, patients with the same sydrome showing characteristic similar patterns. In phenylketonuria a high phenylalanine output and a raised plasma level were found with a normal clearance. This suggests an overflow mechanism due only to the renal threshold of phenylalanine being exceeded. Conversely, low or normal plasma levels were found with the amino acidurias observed in the adult form of the Fanconi syndrome, the Hartnup syndrome and beta-aminoisobutyric aciduria. This suggests defective renal tubular reabsorption of specific amino acids consistent with previous views based on paper chromatography. The approximate plasma clearances of certain amino acids were of the order to be expected of the glomerular filtration rate. The ion-exchange method also proved convenient for the quantitative determination of beta-aminoisobutyric acid. Assays on specimens from 24 healthy subjects gave results compatible with published genetical researches using paper chromatography.