title: Biosynthesis of a cyclic tautomer of (3-methylmaleyl)acetone from 4-hydroxy-3,5-dimethylbenzoate by Pseudomonas sp. HH35 but not by Rhodococcus rhodochrous N75.
abstract: Here we report that the bacterial catabolism of 4-hydroxy-3,5-dimethylbenzoic acid 1 takes a different course in Rhodococcus rhodochrous N75 and Pseudomonas sp. strain HH35. The former organism accumulates a degradation metabolite of the acid which we isolated and identified as 2,6-dimethylhydroquinone 2. The latter bacterial strain converts the acid and the hydroquinone into a dead-end metabolite. This novel compound was characterised unequivocally by mass spectrometry and 1H and 18C NMR and UV spectroscopy as 4-acetonyl-4-hydroxy-2-methylbut-2-en-1,4-olide 4, a cyclic tautomer of (3-methylmaleyl)acetone, which exists as the enol carboxylate form 8 in aqueous solution.
authors.affiliation: Department of Biological and Nutritional Sciences, The University, Newcastle upon Tyne, United Kingdom.
authors.forename: R B
authors.initials: RB
authors.lastname: Cain
authors.forename: P
authors.initials: P
authors.lastname: Fortnagel
authors.forename: S
authors.initials: S
authors.lastname: Hebenbrock
authors.forename: G W
authors.initials: GW
authors.lastname: Kirby
authors.forename: H J
authors.initials: HJ
authors.lastname: McLenaghan
authors.forename: G V
authors.initials: GV
authors.lastname: Rao
authors.forename: S
authors.initials: S
authors.lastname: Schmidt
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives; D001565:Benzoates / Q000378:metabolism*; D001711:Biotransformation; D005663:Furans / Q000378:metabolism; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008298:Maleates / Q000378:metabolism*; D010101:Oxygen Consumption; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D012240:Rhodococcus / Q000254:growth & development / Q000378:metabolism*
chemical_list: D001565:Benzoates; D005663:Furans; D008298:Maleates; C011905:maleoylacetic acid; C094650:3,5-dimethylbenzoic acid; C004511:butenolide; D015107:4-Butyrolactone