PMID:7727395

Citation	Ensign, SA (1995) Reactivity of carbon monoxide dehydrogenase from Rhodospirillum rubrum with carbon dioxide, carbonyl sulfide, and carbon disulfide. Biochemistry 34:5372-8
Abstract	The reactivities of CO2 and the related compounds COS and CS2 with the nickel- and iron- sulfur-containing carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum have been investigated. Both CO2 and COS were substrates for CODH in a reductant-dependent reaction resulting in the formation of CO. CO2 was reduced to CO and H2O, while COS was reduced to CO and H2S. CO was a potent inhibitor of CO2 reduction at dissolved concentrations as low as 1 microM, but this inhibition could be prevented by quantitatively trapping CO as it was formed by including reduced hemoglobin in the assays. The addition of hemoglobin to the assays also allowed the formation of CO to be monitored in real time by following the decrease in absorbance at 433 nm resulting from carboxyhemoglobin formation. A variety of low-potential reductants, including dithionite, titanium(III) citrate, and dithionite-reduced viologens (methyl and benzyl), were suitable electron donors for the reduction of CO2 and COS. Dithionite-reduced methyl viologen supported the highest rates of CO2 and COS reduction, and the stimulation of CO2 reduction (170-fold increased rate over dithionite alone) was much more dramatic than the stimulation of COS reduction (2.6-fold increased rate over dithionite alone). CO2 was reduced to CO with a Km for CO2 of 190 microM and a Vmax of 44 mumol of CO formed min-1 (mg of protein)-1, while COS was reduced with a Km for COS of 2.2 microM and a Vmax of 0.51 mumol of CO formed min-1 (mg of protein)-1.(ABSTRACT TRUNCATED AT 250 WORDS)
Links	PubMed
Keywords	Aldehyde Oxidoreductases/isolation & purification; Aldehyde Oxidoreductases/metabolism; Carbon Dioxide/metabolism; Carbon Disulfide/metabolism; Chromatography; Chromatography, DEAE-Cellulose; Chromatography, Gas; Durapatite; Hot Temperature; Kinetics; Molecular Weight; Multienzyme Complexes; Rhodospirillum rubrum/enzymology; Rhodospirillum rubrum/growth & development; Spectrophotometry; Substrate Specificity; Sulfur Oxides/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RHORU:COOS	enables	GO:0016491: oxidoreductase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
RHORU:COOS		GO:0016491: oxidoreductase activity	ECO:0000314:		F		Figure 5 shows CO and H2S production from COS reduction via CODH.	complete CACAO 3341

References

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