Microbially-catalyzed conjugation of GABA and tyramine to bile acids.

Bile acids (BAs) are cholesterol-derived molecules in the human gut that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence gut microbiome composition. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate other classes of amines to BAs. We show that