The enzyme argininosuccinate lyase (ASL) generates the amino acid arginine, the precursor to both urea and nitric oxide. However, arginine supplementation is not sufficient to correct all of the symptoms of individuals with a congenital deficiency of this enzyme. Ayelet Erez et al. explain this paradox by showing that ASL has a role in nitric oxide synthesis that is independent of its catalytic activity and provide evidence that therapy with agents boosting nitric oxide levels might be beneficial in ASL-deficient individuals.
- Ayelet Erez
- Sandesh C S Nagamani
- Brendan Lee