Study of the intestinal tyrosine metabolism using stable isotopes and gas chromatography-mass spectrometry

J Chromatogr. 1976 Nov 3;126:569-80. doi: 10.1016/s0021-9673(01)84102-9.


Deuterated tyrosine, 4-hydroxyphenyllactic acid, 4-hydroxyphenylpropionic acid, 4-hydroxyphenylacetic acid and 4-hydroxybenzoic acid were incubated under anaerobic conditions with human faecal specimens for the in vitro study of their respective metabolisms. After 1 week, aromatic acids and phenols were extracted and analyzed by gas chromatography-mass spectrometry. [3',5'-2H2]Tyrosine produced 4-hydroxyphenyllactic acid, 4-hydroxyphenylpropionic acid and 4-hydroxyphenylacetic acid; [3',5'-2H2]-4'-hydroxyphenyllactic acid produced 4-hydroxyphenylpropionic acid, 3-hydroxyphenylpropionic acid, 4-hydroxyphenylacetic acid and phenylproionic acid; [3',5'-2H2]-4'-hydroxyphenyl-propionic acid produced 3-hydroxyphenylpropionic acid and phenylpropionic acid; [3',5',2,2-2H4]-4'-Hydroxyphenylacetic acid produced p-cresol; and [3',5'-2H2]-4'-hydroxybenzoic acid produced phenol. Thus the intestinal flora showed activities for decarboxylation leading to phenol and p-cresol, dehydroxylation leading to phenylpropionic acid and rearrangement leading to 3-hydroxyphenylpropionic acid. Rentention of both deuterium labels was observed in the rearrangement reaction.

MeSH terms

  • Anaerobiosis
  • Chromatography, Gas
  • Feces / analysis
  • Humans
  • Intestine, Large / metabolism*
  • Mass Spectrometry
  • Tyrosine / metabolism*


  • Tyrosine