Metabolism of Styrene Oxide and 2-Phenylethanol in the Styrene-Degrading Xanthobacter Strain 124X.
01 Nov 1989-Applied and Environmental Microbiology (American Society for Microbiology)-Vol. 55, Iss: 11, pp 2850-2855
TL;DR: Styrene oxide and 2-phenylethanol metabolism in the styrene-degrading Xanthobacter sp.
Abstract: Styrene oxide and 2-phenylethanol metabolism in the styrene-degrading Xanthobacter sp. strain 124X was shown to proceed via phenylacetaldehyde and phenylacetic acid. In cell extracts 2-phenylethanol was oxidized by a phenazine methosulfate-dependent enzyme, probably a pyrroloquinoline quinone enzyme. Xanthobacter sp. strain 124X also contains a novel enzymatic activity designated as styrene oxide isomerase. Styrene oxide isomerase catalyzes the isomerization of styrene oxide to phenylacetaldehyde. The enzyme was partially purified and shown to have a very high substrate specificity. Of the epoxides tested, styrene oxide was the only substrate transformed. The initial step in styrene metabolism in Xanthobacter sp. strain 124X is oxygen dependent and probably involves oxidation of the aromatic nucleus.
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...(9), with 15 mM glucose as the sole carbon source....
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...This bacterium is well known for its remarkable tolerance to a range of chemical stressors (Hartmans et al., 1989; Heipieper and de Bont, 1994; Kieboom and de Bont, 2001; Kieboom et al., 1998; Koopman et al., 2009), and has previously been used in biotransformations of other toxic substrates (de…...
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References
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Journal Article•
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
289,852 citations
"Metabolism of Styrene Oxide and 2-P..." refers methods in this paper
...method with bovine serum albumin as the standard (10)....
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TL;DR: In this paper, simple group-contribution methods are proposed to estimate eleven important physical properties of pure materials, and a common set of structural groups is employed to achieve high accuracy but not claimed to be as accurate as or more accurate than techniques in common use today.
Abstract: Simple group-contribution methods are proposed to estimate eleven important physical properties of pure materials. A common set of structural groups was employed. High accuracy is not claimed, but the proposed methods are often as accurate as or more accurate than techniques in common use today.
1,573 citations
TL;DR: Observations do not provide arguments for the view that quinoproteins have a unique role in microbial oxidations, and further comparative studies on oxidoreductases are necessary to reveal the special features of this novel group of enzymes.
Abstract: Pyrroloquinoline quinone (PQQ) is found in a wide range of microorganisms, and several bacteria even excrete this compound into their culture medium when grown on alcohols. The existence of different classes of quinoprotein (PQQ-containing) enzymes is now well established (alcohol dehydrogenases, aldose (glucose) dehydrogenases, amine dehydrogenases and amine oxidases) while several other enzymes are suspected to be quinoproteins. In addition, many bacteria produce a quinoprotein apoenzyme, e.g., Escherichia coli and Pseudomonas testosteroni, producing glucose and ethanol dehydrogenase apoenzyme, respectively. It is unclear why these bacteria do not produce the holoenzyme form, but the apoenzymes have the ability to become functional, as was shown when the organisms were provided with PQQ. With this approach it could be demonstrated that E. coli has a non-phosphorylative route of glucose dissimilation via gluconate. Also, results with mixed cultures indicate that PQQ is a growth factor for certain bacteria under certain conditions. Despite the relatively high redox potential of the PQQ/PQQH2 couple, quinoproteins transfer electrons to a variety of natural electron acceptors. Depending on the type of quinoprotein enzyme, the following components of the respiratory chain appear to be active: cytochrome c (sometimes with a copper protein as an intermediate), cytochrome b, and NADH dehydrogenase. PQQ is not restricted to a particular group of organisms, and reactions catalysed by quinoproteins can also be performed by NAD(P)-dependent or flavoprotein enzymes. Thus, these observations do not provide arguments for the view that quinoproteins have a unique role in microbial oxidations. Further comparative studies on oxidoreductases are necessary to reveal the special features of this novel group of enzymes.
93 citations
Additional excerpts
...This stimulation by NH4Cl is similar to that observed with the quinoprotein methanol dehydrogenase (5)....
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TL;DR: A pathway for styrene metabolism through the intermediary formation of phenylacetate and o-hydroxyphenylacetic acids which is further oxidized via homogentisate is suggested and discussed.
77 citations
"Metabolism of Styrene Oxide and 2-P..." refers background in this paper
...styrene oxide in microorganisms, although styrene-utilizing bacteria have been isolated (1, 12)....
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...(1) could possibly, in combination with the assumption that styrene is oxidized to styrene oxide, also be explained by assuming the presence of SOI activity....
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TL;DR: It is concluded that both dehydrogenases are involved in the metabolism of natural compounds and due to their broad substrate specificity fortuitously also play a role inThe metabolism of the xenobiotic compounds 1,2-dichloroethane and 2-chloroethanol.
Abstract: SUMMARY: An inducible methanol dehydrogenase showing high activity with 2-chloroethanol was purified from 2-chloroethanol-grown cells of the 1, 2-dichloroethane utilizing bacterium Xanthobacter autotrophicus GJ10. The enzyme consisted of a 60 kDa polypeptide that was associated with a 10 kDa polypeptide and contained pyrrolo-quinoline quinone (PQQ) as a prosthetic group. Chloroethanol-grown cells of strain GJ10 also contained an inducible NAD-dependent chloroacetaldehyde dehydrogenase. Its involvement in the metabolism of 2-chloroethanol was inferred from its absence in a 2-chloroethanol non-utilizing mutant. Three different isolates of X. autotrophicus that do not utilize 2-chloroethanol for growth produced chloroethanol dehydrogenase and chloroacetaldehyde dehydrogenase activities at similar levels as strain GJ10. It is concluded that both dehydrogenases are involved in the metabolism of natural compounds and due to their broad substrate specificity fortuitously also play a role in the metabolism of the xenobiotic compounds 1,2-dichloroethane and 2-chloroethanol.
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