Vanillate monooxygenase

• CAS Number: 39307-11-4

The vanillate monooxygenase ( VAN, EC 1.14.13.82 ), also referred to as vanillate demethylase, catalyzes the conversion of vanillate, the anion of vanillic acid to protocatechuic acid. This NADH is oxidized to NAD , depending on the species but can also act as an electron donor NADPH. As a monooxygenase enzyme oxygen (O2 ) is consumed with formaldehyde and water are formed:

VAN was identified in Pseudomonas, Acinetobacter and Corynebacteriumstämmen.

The vanillate monooxygenase is a heterodimeric enzyme and is composed of an oxygenase and a Oxidoreduktaseuntereinheit. The former is from the vanA gene, temptation encoded by vanB gene, they are close homologs. VanB also has a conserved NAD -ribose - binding domain and an iron -sulfur domain.

The conversion of vanillate to protocatechuic an intermediate step in the degradation of lignin. While white-rot fungi depolymerize lignin, bacterial microorganisms can convert the resulting aromatic degradation construction products. In protocatechuic finally there is a ring cleavage and further metabolism. The liberated in the reaction catalyzed by VAN formaldehyde is converted by a glutathione -dependent formaldehyde dehydrogenase (EC 1.2.1.1 ), as it is very toxic.