Converts alpha-amino-beta-carboxymuconate-epsilon-semialdehyde (ACMS) to alpha-aminomuconate semialdehyde (AMS). 2-amino-3-carboxymuconate 6-semialdehyde + H(+) = 2-aminomuconate 6-semialdehyde + CO2 Secondary metabolite metabolism; quinolate metabolism. Monomer. Belongs to the metallo-dependent hydrolases superfamily. ACMSD family.