MetaCyc Enzyme: aldehyde decarbonylase

Gene: SYNPCC7942_1593

Species: Synechococcus elongatus PCC 7942

Purified aldehyde decarbonylase from Synechococcus elongatus PCC 7942 was able to decarbonylate fatty aldehydes. When expressed in Escherichia coli along with acyl-[acp] reductase, it conferred on the host organism the ability to produce alkanes.

Unlike the membrane-bound aldehyde decarbonylases from higher plants and green algae, the cyanobacterial enzyme is soluble. The enzyme contains a diiron center, and belongs to the dinuclear iron oxygenase family, which also includes methane monooxygenase, type I ribonucleotide reductase, and ferritin.

In vitro decarbonylation was only observed in the presence of ferredoxin, ferredoxin reductase and NADPH, a common feature of diiron-containing enzymes [Schirmer10]. The enzyme was Originally thought to produce carbon monoxide, but subsequent analysis showed that the actual product is formate [Warui11].

The authors suggested that despite the fact that the reaction appears to be a hydrolysis, the enzyme may possess a "cryptic" oxygenase activity, since all known dinuclear iron enzymes are oxygenases [Warui11]. Studies of homologous enzymes from 4 different cyanobacterial species initially suggested that the enzyme is much more active under anaerobic conditions, where it catalyzes a simple hydrolysis reaction (even though a reduction sysytem was absolutely necessary for activity) [Das11, Eser11]. However, reproduction of this work found that the results were moslt likely due to oxygen contamination of the assays, and that the enzyme is indeed an oxygenase [Li12e].

Map Position: [1,660,025 -> 1,660,720]

Molecular Weight of Polypeptide: 26.369 kD (from nucleotide sequence)

Unification Links: Entrez-gene:3775017 , NCBI Entrez Protein (GI):81169283 , Protein Model Portal:Q54764 , SMR:Q54764 , String:1140.Synpcc7942_1593 , UniProt:Q54764

Relationship Links: InterPro:IN-FAMILY:IPR009078 , InterPro:IN-FAMILY:IPR012347 , InterPro:IN-FAMILY:IPR022612 , Pfam:IN-FAMILY:PF11266

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Enzymatic reaction of: long-chain aldehyde decarbonylase

EC Number:

a long-chain aldehyde + 2 NADPH + oxygen + H+ <=> an alkane + formate + 2 NADP+ + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: alkane biosynthesis I

Cofactors or Prosthetic Groups: diiron [Schirmer10]

Enzymatic reaction of: octadecanal decarbonylase (aldehyde decarbonylase)

EC Number:

octadecanal + 2 NADPH + oxygen + H+ <=> heptadecane + formate + 2 NADP+ + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: heptadecane biosynthesis

Cofactors or Prosthetic Groups: diiron [Schirmer10]


Das11: Das D, Eser BE, Han J, Sciore A, Marsh EN (2011). "Oxygen-independent decarbonylation of aldehydes by cyanobacterial aldehyde decarbonylase: a new reaction of diiron enzymes." Angew Chem Int Ed Engl 50(31);7148-52. PMID: 21671322

Eser11: Eser BE, Das D, Han J, Jones PR, Marsh EN (2011). "Oxygen-independent alkane formation by non-heme iron-dependent cyanobacterial aldehyde decarbonylase: investigation of kinetics and requirement for an external electron donor." Biochemistry 50(49);10743-50. PMID: 22074177

Li12e: Li N, Chang WC, Warui DM, Booker SJ, Krebs C, Bollinger JM (2012). "Evidence for only oxygenative cleavage of aldehydes to alk(a/e)nes and formate by cyanobacterial aldehyde decarbonylases." Biochemistry 51(40);7908-16. PMID: 22947199

Schirmer10: Schirmer A, Rude MA, Li X, Popova E, del Cardayre SB (2010). "Microbial biosynthesis of alkanes." Science 329(5991);559-62. PMID: 20671186

Warui11: Warui DM, Li N, Norgaard H, Krebs C, Bollinger JM, Booker SJ (2011). "Detection of Formate, Rather than Carbon Monoxide, As the Stoichiometric Coproduct in Conversion of Fatty Aldehydes to Alkanes by a Cyanobacterial Aldehyde Decarbonylase." J Am Chem Soc. PMID: 21341652

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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