This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Yu, C. L.
Right arrow Articles by Subramanian, M.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yu, C. L.
Right arrow Articles by Subramanian, M.

 Previous Article  |  Next Article 

Journal of Bacteriology, July 2009, p. 4624-4632, Vol. 191, No. 14
0021-9193/09/$08.00+0     doi:10.1128/JB.00409-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Two Distinct Pathways for Metabolism of Theophylline and Caffeine Are Coexpressed in Pseudomonas putida CBB5{triangledown} ,{dagger}

Chi Li Yu, Tai Man Louie, Ryan Summers, Yogesh Kale, Sridhar Gopishetty, and Mani Subramanian*

Center for Biocatalysis & Bioprocessing and Department of Chemical & Biochemical Engineering, The University of Iowa, Iowa City, Iowa 52242

Received 26 March 2009/ Accepted 7 May 2009

Pseudomonas putida CBB5 was isolated from soil by enrichment on caffeine. This strain used not only caffeine, theobromine, paraxanthine, and 7-methylxanthine as sole carbon and nitrogen sources but also theophylline and 3-methylxanthine. Analyses of metabolites in spent media and resting cell suspensions confirmed that CBB5 initially N demethylated theophylline via a hitherto unreported pathway to 1- and 3-methylxanthines. NAD(P)H-dependent conversion of theophylline to 1- and 3-methylxanthines was also detected in the crude cell extracts of theophylline-grown CBB5. 1-Methylxanthine and 3-methylxanthine were subsequently N demethylated to xanthine. CBB5 also oxidized theophylline and 1- and 3-methylxanthines to 1,3-dimethyluric acid and 1- and 3-methyluric acids, respectively. However, these methyluric acids were not metabolized further. A broad-substrate-range xanthine-oxidizing enzyme was responsible for the formation of these methyluric acids. In contrast, CBB5 metabolized caffeine to theobromine (major metabolite) and paraxanthine (minor metabolite). These dimethylxanthines were further N demethylated to xanthine via 7-methylxanthine. Theobromine-, paraxanthine-, and 7-methylxanthine-grown cells also metabolized all of the methylxanthines mentioned above via the same pathway. Thus, the theophylline and caffeine N-demethylation pathways converged at xanthine via different methylxanthine intermediates. Xanthine was eventually oxidized to uric acid. Enzymes involved in theophylline and caffeine degradation were coexpressed when CBB5 was grown on theophylline or on caffeine or its metabolites. However, 3-methylxanthine-grown CBB5 cells did not metabolize caffeine, whereas theophylline was metabolized at much reduced levels to only methyluric acids. To our knowledge, this is the first report of theophylline N demethylation and coexpression of distinct pathways for caffeine and theophylline degradation in bacteria.

* Corresponding author. Mailing address: Center for Biocatalysis & Bioprocessing, The University of Iowa, Oakdale Research Park, 2501 Crosspark Road, Suite C100, Coralville, IA 52241. Phone: (319) 335-4900. Fax: (315) 339-4901. E-mail: mani-subramanian{at}uiowa.edu

{triangledown} Published ahead of print on 15 May 2009.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

Journal of Bacteriology, July 2009, p. 4624-4632, Vol. 191, No. 14
0021-9193/09/$08.00+0     doi:10.1128/JB.00409-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»