Direct ring fission of salicylate by a salicylate 1,2-dioxygenase activity from Pseudaminobacter salicylatoxidans.
In cell extracts of Pseudaminobacter salicylatoxidans strain BN12, an enzymatic activity was detected which converted salicylate in an oxygen-dependent but NAD(P)H-independent reaction to a product with an absorbance maximum at 283 nm. This metabolite was isolated, purified, and identified by mass spectrometry and (1)H and (13)C nuclear magnetic resonance spectroscopy as 2-oxohepta-3,5-dienedioic acid. This metabolite could be formed only by direct ring fission of salicylate by a 1,2-dioxygenase reaction. Cell extracts from P. salicylatoxidans also oxidized 5-aminosalicylate, 3-, 4-, and 5-chlorosalicylate, 3-, 4-, and 5-methylsalicylate, 3- and 5-hydroxysalicylate (gentisate), and 1-hydroxy-2-naphthoate. The dioxygenase was purified and shown to consist of four identical subunits with a molecular weight of about 45,000. The purified enzyme showed higher catalytic constants with gentisate or 1-hydroxy-2-naphthoate than with salicylate. It was therefore concluded that P. salicylatoxidans synthesized a gentisate 1,2-dioxygenase with an extraordinary substrate range, which also allowed the oxidation of salicylate.
Hintner
J P
JP
Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
Lechner
C
C
Riegert
U
U
Kuhm
A E
AE
Storm
T
T
Reemtsma
T
T
Stolz
A
A
D002851:Chromatography, High Pressure Liquid; D049308:Dioxygenases; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology*; D012459:Salicylates / Q000378:metabolism*; D013379:Substrate Specificity
D012459:Salicylates; D010105:Oxygenases; D049308:Dioxygenases; C026247:gentisate 1,2-dioxygenase