In enzymology, a 3-hydroxybenzoate 2-monooxygenase is an enzyme that catalyzes the chemical reaction 3-hydroxybenzoate + AH2 + O2 ⇌ {\displaystyle \rightleftharpoons } 2,3-dihydroxybenzoate + A + H2OThe 3 substrates of this enzyme are 3-hydroxybenzoate, an electron acceptor AH2, and O2, whereas its 3 products are 2,3-dihydroxybenzoate, the reduction product A, and H2O. Wikipedia