title: Protocatechuate 3,4-dioxygenase: a wide substrate specificity enzyme isolated from Stenotrophomonas maltophilia KB2 as a useful tool in aromatic acid biodegradation.
abstract: Protocatechuate 3,4-dioxygenases (P34Os) catalyze the reaction of the ring cleavage of aromatic acid derivatives. It is a key reaction in many xenobiotic metabolic pathways. P34Os characterize narrow substrate specificity. This property is an unfavorable feature in the biodegradation process because one type of pollution is rarely present in the environment. Thus, the following study aimed at the characterization of a P34O from Stenotrophomonas maltophilia KB2, being able to utilize a wide spectrum of aromatic carboxylic acids. A total of 3 mM vanillic acid and 4-hydroxybenzoate were completely degraded during 8 and 4.5 h, respectively. When cells of strain KB2 were grown on 9 mM 4-hydroxybenzoate, P34O was induced. Biochemical analysis revealed that the examined enzyme was similar to other known P34Os, but showed untypical wide substrate specificity. A high activity of P34O against 2,4- and 3,5-dihydroxybenzoate was observed. As these substrates do not possess ortho configuration hydroxyl groups, it is postulated that their cleavage could be connected with their monodentate binding of substrate to the active site. Since this enzyme characterizes untypical wide substrate specificity it makes it a useful tool in applications for environmental clean-up purposes.
authors: Department of Biochemistry, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland.
authors: Urszula
authors: U
authors: Guzik
authors: Katarzyna
authors: K
authors: Hupert-Kocurek
authors: Małgorzata
authors: M
authors: Sitnik
authors: Danuta
authors: D
authors: Wojcieszyńska
mesh_terms: D001711:Biotransformation; D002264:Carboxylic Acids / Q000378:metabolism; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004795:Enzyme Stability; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D011520:Protocatechuate-3,4-Dioxygenase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D020615:Stenotrophomonas maltophilia / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002264:Carboxylic Acids; D004269:DNA, Bacterial; D006841:Hydrocarbons, Aromatic; D011520:Protocatechuate-3,4-Dioxygenase