On benzoate therapy for ammonia toxicity

The conjugation of benzoic acid with glycine to form hippuric acid can be useful in ammonia detoxification only if glycine is replenished from endogenous pools of waste nitrogen at a rate sufficient to combat hyperammonemia.1,2 We have examined this requirement with suspensions of isolated hepatocytes from the rat.3 Consistent with previous studies with intact animals, the conversion of benzoate to hippurate was stimulated by glycine (4x) or glyoxylate (2.6x), the α-keto analogue of glycine. Thus, glycine is clearly limiting in hippurate synthesis.