Background of the database
Anthropogenic compounds are widely distributed in nature and toxic for living beings. The degradation of these compounds is essential to clean up the environment. Many microbial enzymes are involved in the degradation of these compounds. Oxygenases are one of them that oxidize theses compounds by incorporating oxygen atom(s). Monooxygenase and dioxygenase are two main groups of the oxygenases. Monooxygenases incorporate one oxygen atom to substrate and reduce the other oxygen atom to water whereas Dioxygenases incorporate both atoms of molecular oxygen into substrate. Dioxygenases are more diverse than monoxygenases and play crucial role of the degradation of aromatic compounds. Aromatic dioxygenases are divided into two subfamilies: Aromatic Ring hydroxylating dioxygenases(ARHD) and Aromatic ring Cleavage dioxygenases(ARCD). ARHD incorporate two atoms of dioxygen into their substrates in the dixydroxylation reaction, and cis-diols are formed. This reaction also requires NAD(P)H as an electrodonor. Aromatic-ring-cleavage dioxygenases incorporate two atoms of dioxygen into aromatic substrates, typically carrying two or more hydroxyl groups on the aromatic ring and the aromatic ring is cleaved. This reaction does not require an external reductant. Aromatic ring cleavage dioxygenase further divides into two subfamilies based on mode of ring cleavage: extradiol and intradiol. Intradiol dioxygenases utilize non-heme Fe(III) to cleave the aromatic nucleus ortho to the hydroxyl substituents; and extradiol dioxygenases utilize non-heme Fe(II) or other divalent metal ions to cleave the aromatic nucleus meta to hydroxyl substituents.
Content of database
The database contains information on over 240 oxygenases including both dioxygenases and monooxygenases involved in the biodegradation on xenobiotic compounds. The enzyme entries contain their EC number, synonym, reaction in which they involved, Family and subfamily, Structure and Gene link and literature citation. The entries also linked to several external database including BRENDA, LIGAND, ENZYME and UM-BBD providing wide background information.