Note: a dashed line (without arrowheads) between two compound names is meant to imply that the two names are just different instantiations of the same compound -- i.e. one may be a specific name and the other a general name, or they may both represent the same compound in different stages of a polymerization-type pathway. This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Degradation/Utilization/Assimilation → Alcohols Degradation|
Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer that is used in paper and textile mills and in copolymers as a biodegradable segment. PVA is the only xenobiotic carbon-chain polymer that is known to be biodegradable at high molecular weights [HirotaMamoto06]. The pathway for its degradation has been studied in several organisms, including Brevundimonas vesicularis [Watanabe76], Alcaligenes faecalis KK314 [Matsumura99a], Pseudomonas sp. strain VM15C [Shimao89, Shimao00] and Sphingopyxis sp. 113P3 [Klomklang05].
The major route of polyvinyl alcohol(n) degradation involves its importation into the periplasm, where it is oxidized by polyvinyl alcohol dehydrogenase (cytochrome) to oxidized polyvinyl alcohol(n), which is then hydrolyzed by oxidized polyvinylalcohol hydrolase, releasing acetate monomers. A PVA oxidase enzyme has also been reported n earlier works [Shimao82, Shimao85]. However, it is not clear whether this enzyme actually exists.
PVA dehydrogenase enzymes have been purified from several organisms including Sphingopyxis sp. 113P3, and all appear to be quinohaemoprotein that contain pyrroloquinoline quinone [Hatanaka95]. The enzymes show a somewhat broad substrate specificity with 1, 3-diols, although PVA is the most favorable substrate.
The genes encoding these enzymes have been cloned from several organisms [HirotaMamoto06, Shimao96, Shimao00, Klomklang05]. In addition, the gene encoding the native cytochrome c from Sphingopyxis sp. 113P3 has been cloned and expressed in Escherichia coli. The recombinant cytochrome c was fully reduced by PVA when coupled with a catalytic amount of the recombinant PVA dehydrogenase, suggesting that the cytochrome c is the physiological primary electron acceptor for the enzyme and that PVA dehydrogenation is linked with the respiratory chain in Sphingopyxis sp. 113P3 [Mamoto08].
In Sphingopyxis sp. 113P3 the genes encoding oxidized polyvinylalcohol hydrolase (oph), polyvinyl alcohol dehydrogenase (cytochrome) (pvaA) and cytochrome c (cytC) are located in a single operon on a megaplasmid. The operon is constitutively expressed, although expression is enhanced by PVA [Hu08].
HirotaMamoto06: Hirota-Mamoto R, Nagai R, Tachibana S, Yasuda M, Tani A, Kimbara K, Kawai F (2006). "Cloning and expression of the gene for periplasmic poly(vinyl alcohol) dehydrogenase from Sphingomonas sp. strain 113P3, a novel-type quinohaemoprotein alcohol dehydrogenase." Microbiology 152(Pt 7);1941-9. PMID: 16804170
Hu08: Hu X, Mamoto R, Fujioka Y, Tani A, Kimbara K, Kawai F (2008). "The pva operon is located on the megaplasmid of Sphingopyxis sp. strain 113P3 and is constitutively expressed, although expression is enhanced by PVA." Appl Microbiol Biotechnol 78(4);685-93. PMID: 18214469
Klomklang05: Klomklang W, Tani A, Kimbara K, Mamoto R, Ueda T, Shimao M, Kawai F (2005). "Biochemical and molecular characterization of a periplasmic hydrolase for oxidized polyvinyl alcohol from Sphingomonas sp. strain 113P3." Microbiology 151(Pt 4);1255-62. PMID: 15817792
Mamoto08: Mamoto R, Hu X, Chiue H, Fujioka Y, Kawai F (2008). "Cloning and expression of soluble cytochrome c and its role in polyvinyl alcohol degradation by polyvinyl alcohol-utilizing Sphingopyxis sp. strain 113P3." J Biosci Bioeng 105(2);147-51. PMID: 18343342
Shimao00: Shimao M, Tamogami T, Kishida S, Harayama S (2000). "The gene pvaB encodes oxidized polyvinyl alcohol hydrolase of Pseudomonas sp. strain VM15C and forms an operon with the polyvinyl alcohol dehydrogenase gene pvaA." Microbiology 146 ( Pt 3);649-57. PMID: 10746768
Shimao85: Shimao M, Nishimura Y, Kato N, Sakazawa C (1985). "Localization of Polyvinyl Alcohol Oxidase Produced by a Bacterial Symbiont, Pseudomonas sp. Strain VM15C." Appl Environ Microbiol 49(1);8-10. PMID: 16346711
Shimao89: Shimao M, Onishi S, Kato N, Sakazawa C (1989). "Pyrroloquinoline Quinone-Dependent Cytochrome Reduction in Polyvinyl Alcohol-Degrading Pseudomonas sp. Strain VM15C." Appl Environ Microbiol 55(2);275-278. PMID: 16347841
Shimao96: Shimao M, Tamogami T, Nishi K, Harayama S (1996). "Cloning and characterization of the gene encoding pyrroloquinoline quinone-dependent poly(vinyl alcohol) dehydrogenase of Pseudomonas sp. strain VM15C." Biosci Biotechnol Biochem 60(7);1056-62. PMID: 8782398
Watanabe76: Watanabe Y, Hamada N, Morita M, Tsujisaka Y (1976). "Purification and properties of a polyvinyl alcohol-degrading enzyme produced by a strain of Pseudomonas." Arch Biochem Biophys 174(2);575-81. PMID: 820265
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