2-Amino 3-carboxymuconate 6-semialdehyde decarboxylase (ACMSD, EC ) plays a key role in tryptophan catabolism. By diverting 2-amino 3-carboxymuconate semialdehyde from quinolinate production, the enzyme regulates NAD biosynthesis from the amino acid, directly affecting quinoli-nate and picolinate formation.