The enzyme does not act on unsubstituted aliphatic or aromatic aldehydes or glucose; NAD+ can replace NADP+, but with lower affinity. The enzyme was initially believed to act on 4-carboxy-2-hydroxy-cis,cis-muconate 6-semialdehyde and produce 4-carboxy-2-hydroxy-cis,cis-muconate [1]. However, later studies showed that the substrate is the hemiacetal form [3], and the product is 2-oxo-2H-pyran-4,6-dicarboxylate [2,4].
History
EC 1.1.1.312 created 1978 as EC 1.2.1.45, transferred 2011 to EC 1.1.1.312
Masai E, Momose K, Hara H, Nishikawa S, Katayama Y, Fukuda M
Title
Genetic and biochemical characterization of 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase and its role in the protocatechuate 4,5-cleavage pathway in Sphingomonas paucimobilis SYK-6.