Caffeine dehydrogenase

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 Caffeine dehydrogenase Subunit beta.png
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EC no. 1.17.5.2
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Caffeine dehydrogenase, commonly referred to in scientific literature as caffeine oxidase (EC 1.17.5.2), is an enzyme with the systematic name caffeine:ubiquinone oxidoreductase. [1] The enzyme is most well known for its ability to directly oxidize caffeine, a type of methylxanthine, to trimethyluric acid. [2] Caffeine dehydrogenase can be found in bacterium Pseudomonas sp. CBB1 and in several species within the genera Alcaligenes , Rhodococcus, and Klebsiella .

Contents

Structure

Caffeine dehydrogenase found in Pseudomonas sp. CBB1 is a heterotrimer with a αβγ structure and is encoded by the gene cdhA. [1] The alpha subunit is the largest of the three, and the gamma subunit is the smallest. The molecular weights of the alpha, beta, and gamma subunits are 90.0 kD, 40.0 kD, and 20.0 kD respectively. However, caffeine dehydrogenase has also been found as a monomeric structure in Alcaligenes sp. strain CF8 (65 kDa) and a Rhodococcus sp.-Klebsiella sp. mixed-culture consortium. [1] The heterotrimer is noted as being similar to the xanthine dehydrogenase found in Veillonella atypica. [1] [3]

Reaction

In comparison to N-demethylases, another class of caffeine-degrading enzymes, caffeine dehydrogenase does not require the use of oxygen, NAD, or NADP as electron acceptors. [4] Instead, caffeine dehydrogenase uses dichlorophenol, indophenol, coenzyme Q0, and cytochrome c as electron acceptors. [1] [4] Caffeine dehydrogenase has been noted as being more stable as well. [4]

Caffeine dehydrogenase is responsible for catalyzing the oxidation of caffeine directly into trimethyluric acid, and the enzyme uses coenzyme Q0, also known as ubiquinone, as an electron acceptor. This is done by incorporating an oxygen atom from a water molecule into the C-8 position, and the overall reaction can be seen in the following chemical reaction:

Caffeine dehydrogenase.svg
caffeine + ubiquinone (Q0 ox) + H2O 1,3,7-trimethyluric acid + ubiquinol (Q0 red)

The enzyme is specific for caffeine, less active on theobromine, and has no activity on xanthine. [5] The product is stoichiometrically produced from caffeine at a 1:1 molar ratio, and there was no hydrogen peroxide byproduct. [1] Enzyme activity is optimal at pH 7.0 in 50 mM potassium phosphate buffer, and activity increased linearly from 298 K to 339 K. [1]

Biological function

Trimethyluric acid can enter the purine catabolic pathway and further break down into other useful compounds. [4] Trimethyluric acid has been reported to break down further into 3, 6, 8-trimethylallantoin by resting cells in a Rhodococcus and Klebsiella mixed culture. [6]

Industrial significance

Caffeine (1,3,7-trimethylxanthine), the substrate in the above reaction, is a purine alkaloid found in a variety of plant species, such as coffee, cacao, cola, and tea leaves. [7] Caffeine has also been used as a cardiac, neurological, and respiratory stimulant. Because of its prevalence in the modern world in the form of beverages, food, and medicine, caffeine has become one of the world's major agro-industrial wastes. [2] Thus, caffeine has become more noticeable in surface water, groundwater, and waste water effluents all over the world. [8] In addition to being an addictive substance, it has also been shown to lead to adverse health effects, such as irregular sleeping patterns, increase in blood pressure, palpitations, and anxiety. [9]

Decaffeination has been traditionally recommended to reduce caffeine content in food and beverages, but to perform decaffeination by physio-chemical treatments is expensive and can produce other waste that may require further treatment. [2] Thus, microbial bioprocessing has begun to appear more attractive, with bacteria that are capable of metabolizing caffeine being considered. Specifically, bacteria containing caffeine dehydrogenase have been seen as helpful in treating caffeine in agro-industrial wastes of coffee pulps and husks, [10] which can then be used to feed farm animals. In addition, the caffeine dehydrogenase found in Alcaligenes species CF8 may be useful in waste treatment and biosensor development. [2]

Caffeine dehydrogenase, when in the presence of a tetrazolium dye, has been shown to be suitable for detecting caffeine in coffee, soda, and milk due to its high specificity for caffeine. [9] Thus, been used to estimate caffeine levels in pharmaceuticals. [9] However, it has been noted that caffeine dehydrogenase would not be useful in the recovery of methylxanthine intermediates that hold pharmaceutical value since the reaction is only a single step. [4]

Related Research Articles

<span class="mw-page-title-main">Caffeine</span> Central nervous system stimulant

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is mainly used recreationally, as a eugeroic (wakefulness promoter) or as a mild cognitive enhancer to increase alertness and attentional performance. Caffeine acts by blocking binding of adenosine to the adenosine A1 receptor, which enhances release of the neurotransmitter acetylcholine. Caffeine has a three-dimensional structure similar to that of adenosine, which allows it to bind and block its receptors. Caffeine also increases cyclic AMP levels through nonselective inhibition of phosphodiesterase.

<span class="mw-page-title-main">Xanthine</span> Chemical compound

Xanthine is a purine base found in most human body tissues and fluids, as well as in other organisms. Several stimulants are derived from xanthine, including caffeine, theophylline, and theobromine.

<span class="mw-page-title-main">Xanthine oxidase</span> Class of enzymes

Xanthine oxidase is a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species. These enzymes catalyze the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. These enzymes play an important role in the catabolism of purines in some species, including humans.

<span class="mw-page-title-main">Caffeinated drink</span> Type of drink

A caffeinated drink, or caffeinated beverage, is a drink that contains caffeine, a stimulant that is legal practically all over the world. Some are naturally caffeinated while others have caffeine added as an ingredient.

<span class="mw-page-title-main">Succinate dehydrogenase</span> Enzyme

Succinate dehydrogenase (SDH) or succinate-coenzyme Q reductase (SQR) or respiratory complex II is an enzyme complex, found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes. It is the only enzyme that participates in both the citric acid cycle and the electron transport chain. Histochemical analysis showing high succinate dehydrogenase in muscle demonstrates high mitochondrial content and high oxidative potential.

<i>Pseudomonas putida</i> Species of bacterium

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4-Hydroxybenzoic acid, also known as p-hydroxybenzoic acid (PHBA), is a monohydroxybenzoic acid, a phenolic derivative of benzoic acid. It is a white crystalline solid that is slightly soluble in water and chloroform but more soluble in polar organic solvents such as alcohols and acetone. 4-Hydroxybenzoic acid is primarily known as the basis for the preparation of its esters, known as parabens, which are used as preservatives in cosmetics and some ophthalmic solutions. It is isomeric with 2-hydroxybenzoic acid, known as salicylic acid, a precursor to aspirin, and with 3-hydroxybenzoic acid.

<span class="mw-page-title-main">Paraxanthine</span> Chemical compound

Paraxanthine, also known as 1,7-dimethylxanthine, is a metabolite of theophylline and theobromine, two well-known stimulants found in coffee, tea, and chocolate. It is a member of the xanthine family of alkaloids, which includes caffeine, theobromine, and theophylline.

<span class="mw-page-title-main">6-Phosphogluconate dehydrogenase</span> Class of enzymes

6-Phosphogluconate dehydrogenase (6PGD) is an enzyme in the pentose phosphate pathway. It forms ribulose 5-phosphate from 6-phosphogluconate:

<span class="mw-page-title-main">Electron-transferring-flavoprotein dehydrogenase</span> Protein family

Electron-transferring-flavoprotein dehydrogenase is an enzyme that transfers electrons from electron-transferring flavoprotein in the mitochondrial matrix, to the ubiquinone pool in the inner mitochondrial membrane. It is part of the electron transport chain. The enzyme is found in both prokaryotes and eukaryotes and contains a flavin and FE-S cluster. In humans, it is encoded by the ETFDH gene. Deficiency in ETF dehydrogenase causes the human genetic disease multiple acyl-CoA dehydrogenase deficiency.

<span class="mw-page-title-main">Xylose metabolism</span>

D-Xylose is a five-carbon aldose that can be catabolized or metabolized into useful products by a variety of organisms.

In enzymology, a theobromine synthase is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">(S)-mandelate dehydrogenase</span> Class of enzymes

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<span class="mw-page-title-main">Maleate isomerase</span>

In enzymology, a maleate isomerase, or maleate cis-tran isomerase, is a member of the Asp/Glu racemase superfamily discovered in bacteria. It is responsible for catalyzing cis-trans isomerization of the C2-C3 double bond in maleate to produce fumarate, which is a critical intermediate in citric acid cycle. The presence of an exogenous mercaptan is required for catalysis to happen.

<span class="mw-page-title-main">4-hydroxy-2-oxovalerate aldolase</span> InterPro Family

The enzyme 4-hydroxy-2-oxovalerate aldolase catalyzes the chemical reaction

<span class="mw-page-title-main">8-Phenyltheophylline</span> Chemical compound

8-Phenyltheophylline (8-phenyl-1,3-dimethylxanthine, 8-PT) is a drug derived from the xanthine family which acts as a potent and selective antagonist for the adenosine receptors A1 and A2A, but unlike other xanthine derivatives has virtually no activity as a phosphodiesterase inhibitor. It has stimulant effects in animals with similar potency to caffeine. Coincidentally 8-phenyltheophylline has also been found to be a potent and selective inhibitor of the liver enzyme CYP1A2 which makes it likely to cause interactions with other drugs which are normally metabolised by CYP1A2.

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<span class="mw-page-title-main">Nicotinate dehydrogenase (cytochrome)</span>

Nicotinate dehydrogenase (cytochrome) (EC 1.17.2.1, nicotinic acid hydroxylase, nicotinate hydroxylase) is an enzyme with systematic name nicotinate:cytochrome 6-oxidoreductase (hydroxylating). This enzyme catalyses the following chemical reaction

The enzyme cocaine esterase (EC 3.1.1.84, CocE, hCE2, hCE-2, human carboxylesterase 2; systematic name cocaine benzoylhydrolase) catalyses the reaction

<span class="mw-page-title-main">Plastic degradation by marine bacteria</span> Ability of bacteria to break down plastic polymers

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References

  1. 1 2 3 4 5 6 7 Yu CL, Kale Y, Gopishetty S, Louie TM, Subramanian M (January 2008). "A novel caffeine dehydrogenase in Pseudomonas sp. strain CBB1 oxidizes caffeine to trimethyluric acid". Journal of Bacteriology. 190 (2): 772–6. doi:10.1128/jb.01390-07. PMC   2223706 . PMID   17981969.
  2. 1 2 3 4 Mohapatra BR, Harris N, Nordin R, Mazumder A (September 2006). "Purification and characterization of a novel caffeine oxidase from Alcaligenes species". Journal of Biotechnology. 125 (3): 319–27. doi:10.1016/j.jbiotec.2006.03.018. PMID   16647778.
  3. ↑ Gremer L, Meyer O (June 1996). "Characterization of xanthine dehydrogenase from the anaerobic bacterium Veillonella atypica and identification of a molybdopterin-cytosine-dinucleotide-containing molybdenum cofactor". European Journal of Biochemistry. 238 (3): 862–6. doi:10.1111/j.1432-1033.1996.0862w.x. PMID   8706691.
  4. 1 2 3 4 5 Dash SS, Gummadi SN (December 2006). "Catabolic pathways and biotechnological applications of microbial caffeine degradation". Biotechnology Letters. 28 (24): 1993–2002. doi:10.1007/s10529-006-9196-2. PMID   17009088. S2CID   24096323.
  5. ↑ Mohanty SK, Yu CL, Das S, Louie TM, Gakhar L, Subramanian M (August 2012). "Delineation of the caffeine C-8 oxidation pathway in Pseudomonas sp. strain CBB1 via characterization of a new trimethyluric acid monooxygenase and genes involved in trimethyluric acid metabolism". Journal of Bacteriology. 194 (15): 3872–82. doi:10.1128/JB.00597-12. PMC   3416557 . PMID   22609920.
  6. ↑ Madyastha KM, Sridhar GR (August 1998). "A novel pathway for the metabolism of caffeine by a mixed culture consortium". Biochemical and Biophysical Research Communications. 249 (1): 178–81. doi:10.1006/bbrc.1998.9102. PMID   9705852.
  7. ↑ Steffen, D. G. (2000-01-15). "Chemistry and Health Benefits of Caffeinated Beverages: Symposium Overview". In Parliament, Thomas H.; Ho, Chi-Tang; Schieberle, Peter (eds.). Caffeinated Beverages. ACS Symposium Series. Vol. 754. American Chemical Society. pp. 2–8. doi:10.1021/bk-2000-0754.ch001. ISBN   9780841236547.
  8. ↑ Buerge II, Poiger T, Müller MD, Buser HR (February 2003). "Caffeine, an anthropogenic marker for wastewater comtamination of surface waters". Environmental Science & Technology. 37 (4): 691–700. Bibcode:2003EnST...37..691B. doi:10.1021/es020125z. PMID   12636266.
  9. 1 2 3 Mohanty SK, Yu CL, Gopishetty S, Subramanian M (August 2014). "Validation of caffeine dehydrogenase from Pseudomonas sp. strain CBB1 as a suitable enzyme for a rapid caffeine detection and potential diagnostic test". Journal of Agricultural and Food Chemistry. 62 (31): 7939–46. doi:10.1021/jf501598c. PMID   25019418.
  10. ↑ Mazzafera P (December 2002). "Degradation of caffeine by microorganisms and potential use of decaffeinated coffee husk and pulp in animal feeding". Scientia Agricola. 59 (4): 815–821. doi: 10.1590/s0103-90162002000400030 .
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