RESUMO
The dioxygenolytic catabolism of five C-methylated hydroquinones and 2,6-dichlorohydroquinone in Pseudomonas sp. strain HH35 was elucidated. This organism, which is known to catabolise 2,6-dimethylhydroquinone by 1,2-cleavage, accumulated metabolites from 2-methyl-, 2,3-dimethyl-, 2,5-dimethyl-, 2,3,5-trimethyl- and 2,3,5,6-tetramethylhydroquinone which we isolated and characterised by mass spectrometry and (1)H NMR and UV spectroscopy. The identification of these metabolites defined the impact of methyl groups present in the hydroquinone and showed how each substitution pattern determined the site of the initial enzymic attack. With the exception of the 2,3,5,6-tetramethylhydroquinone, all C-methylated hydroquinones were catabolised by an initial dioxygenolytic cleavage occurring adjacent (1,2- or 3,4-cleavage) to a hydroxy group. In addition, our results indicated that the 2,6-dichlorohydroquinone is catabolised in a similar way by this strain.
Assuntos
Hidroquinonas/metabolismo , Oxigenases/metabolismo , Pseudomonas/metabolismo , Hidroquinonas/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Oxigênio/metabolismo , Pseudomonas/enzimologia , Espectrofotometria UltravioletaRESUMO
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.
Assuntos
Benzoatos/metabolismo , Maleatos/metabolismo , Pseudomonas/metabolismo , Rhodococcus/metabolismo , 4-Butirolactona/análogos & derivados , Biotransformação , Furanos/metabolismo , Isomerismo , Espectroscopia de Ressonância Magnética , Consumo de Oxigênio , Pseudomonas/crescimento & desenvolvimento , Rhodococcus/crescimento & desenvolvimentoRESUMO
The oxidation of morphine by washed-cell incubations of Pseudomonas putida M10 gave rise to a large number of transformation products including hydromorphone (dihydromorphinone), 14 beta-hydroxymorphine, 14 beta-hydroxymorphinone, and dihydromorphine. Similarly, in incubations with oxymorphone (14 beta-hydroxydihydromorphinone) as substrate, the major transformation product was identified as oxymorphol (14 beta-hydroxydihydromorphine). The identities of all these biological products were confirmed by mass spectrometry and 1H nuclear magnetic resonance spectroscopy. This is the first report describing structural evidence for the biological synthesis of 14 beta-hydroxymorphine and 14 beta-hydroxymorphinone. These products have applications as intermediates in the synthesis of semisynthetic opiate drugs.
Assuntos
Derivados da Morfina/farmacocinética , Pseudomonas putida/metabolismo , Analgésicos Opioides/síntese química , Analgésicos Opioides/química , Analgésicos Opioides/farmacocinética , Biotransformação , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Derivados da Morfina/síntese química , Derivados da Morfina/químicaAssuntos
Deutério , Fenilalanina , Trítio , Tirosina , Aminas , Ácido Aspártico , Isótopos de Carbono , Fenômenos Químicos , Química , Cinamatos , Hidroxilação , Marcação por Isótopo , MétodosAssuntos
Alcaloides/biossíntese , Fenóis , Fenômenos Químicos , Química , Oxirredução , Plantas Medicinais/metabolismo , TrítioAssuntos
Alcaloides , Fenóis , Alcaloides/biossíntese , Fenômenos Químicos , Química , Plantas Medicinais/metabolismo , QuinolinasRESUMO
Tracer experiments, supported throughout by the analogous chemical transformations, have firmly established the biosynthetic sequence tyrosine -->norlaudanosoline --> reticuline --> salutaridine --> salutaridinol-I -->thebaine --> codeine --> morphine in Papaver somniferum. In general, the farther a precursor lies along this sequence, the more efficient its conversion to morphine in the intact plant. Several intermediates remain to be discovered, such as those lying between tyrosine and norlaudanosoline and between thebaine and codeine. Proof that morphine is made only by the reticuline-salutaridine route is still lacking and would require a careful comparison of the rate of morphine synthesis with the turnover rates for the various intermediates. More importantly, detailed knowledge of the mechanism of each biochemical step can come only with isolation of the enzyme system involved. The chemical oxidation of (-)-reticuline, to give salutaridine, can only be accomplished in very low (0.02 percent) yield (15, 26), whereas, even with whole plants, the biological incorporation of reticuline into the morphine alkaloids can reach 8 percent (13). One would like to know just how an enzyme system directs the oxidative cyclization of reticuline in the desired sense. Kleinschmidt and Mothes and Fairbairn and Wassel (27) have shown that the latex isolated from opium poppies is capable of transforming tyrosine into morphine. Perhaps further work with opium latex will provide the key to the remaining problems of morphine biosynthesis.