Question

Individuals lacking an enzyme in the urea cycle have severe problems as a result of ammonium accumulation. Administration of benzoic acid stimulates formation of benzoylglycine (hippuric acid), a non-toxic compound that can be excreted in urine. Why does this help?

Answer 1

Hippuric Acid is an acyl glycine produced by the conjugation of benzoic acid and glycine, found as a normal component in urine as a metabolite of aromatic compounds from food. Increased urine hippuric acid content may have antibacterial effects.

Hippuric acid is an acyl glycine formed by the conjugation of benzoic aicd with glycine. Acyl glycines are produced through the action of glycine N-acyltransferase which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine. Hippuric acid is a normal component of urine and is typically increased with increased consumption of phenolic compounds (tea, wine, fruit juices). These phenols are converted to benzoic acid which is then converted to hippuric acidand excreted in the urine. Hippuric acid is the most frequently used biomarker in the biological monitoring of occupational exposure to toluene. This product of solvent biotransformation may be also found in the urine of individuals who have not been exposed to the solvent. A smaller fraction of the absorbed toluene is oxidized to aromatic compounds including ortho-cresol, which is not found significantly in the urine of nonexposed individuals.