Anaerobic metabolism of 2-hydroxybenzoic acid (salicylic acid) by a denitrifying bacterium.
The anaerobic metabolism of 2-hydroxybenzoic acid (salicylic acid) was studied in a denitrifying bacterium. Cells grown with 2-hydroxybenzoate were simultaneously adapted to degrade benzoate. Extract of these cells formed benzoate or benzoyl-CoA when incubated under reducing conditions with salicylate, MgATP, and coenzyme A, suggesting a degradation of 2-hydroxybenzoate via benzoate or benzoyl-CoA. This suggestion was supported by enzyme activity measurements. In extracts of 2-hydroxybenzoate-grown cells, the following enzyme activities were detected: two CoA ligases, one specific for 2-hydroxybenzoate, the other for benzoate, and two different enzyme activities catalyzing the reductive transformation of 2-hydroxybenzoyl-CoA. These findings suggest a degradation of salicylic acid by two new enzymes, 2-hydroxybenzoate-CoA ligase (AMP-forming) and 2-hydroxybenzoyl-CoA reductase (dehydroxylating), catalyzing (1) 2-hydroxybenzoate + MgATP + CoASH --> 2-hydroxybenzoyl-CoA + MgAMP + PPi (2) 2-hydroxybenzoyl-CoA + 2[H] --> benzoyl-CoA + H2O Benzoyl-CoA was dearomatized by reduction of the ring. This represents another case in which benzoyl-CoA is a central intermediate in anaerobic aromatic metabolism.
Bonting
C F
CF
Abteilung Angewandte Mikrobiologie, Universität Ulm, D-89069 Ulm, Germany.
Fuchs
G
G
D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction; D012459:Salicylates / Q000378:metabolism*; D020156:Salicylic Acid
D009566:Nitrates; D012459:Salicylates; D020156:Salicylic Acid