TABLE 2.
Enzyme | Organism | Molecular
mass
(kDa)
|
Localizationb | Apparent
Km
(μM)
|
Sp act
(nkat/mg)
|
Cofactor(s) | |||
---|---|---|---|---|---|---|---|---|---|
SDS-PAGE | Gel filtration | PCE | TCE | PCE | TCE | ||||
PCE-RDase | Dehalococcoides ethenogenes | 51 | NDc | m | ND | 342 | Corrinoid, Fe/Sd | ||
Desulfitobacterium sp. strain PCE-1 | 48 | ND | m | ND | 92 | Corrinoidd | |||
PCE/TCE-RDase | Dehalospirillum multivorans | 57 | 58 | s | 200 | 240 | 2,640 | ∼2,200 | 1 Corrinoid, 8Fe/8Sf |
Dehalobacter restrictus | 60 | 164/71g | m | 20 | 24 | 250 | 338 | 1 Corrinoid, 2[4Fe/4S]h | |
Desulfitobacterium hafniense strain PCE-S | 65 | 198 | m | 10 | 4 | 650 | 690 | 1 Corrinoid, 8Fe/8Sf | |
Desulfitobacterium hafniense strain TCE1 | 59 | ND | m | ND | ND | 190 | 157 | Corrinoidd | |
Desulfitobacterium sp. strain Y51 | 58 | 67 | s | 106 | 535 | 2.7 | 13.5 | Corrinoidd | |
Clostridium bifermentans strain DPH-1 | 35 | 70 | s | 12 | 1.2 | Corrinoidd | |||
TCE-RDase | Dehalococcoides ethenogenes | 61 | ND | m | ND | 200 | Corrinoid, Fe/Sd | ||
pH opti- mum | Temp optimum (°C) | Oxygen sensitivity half-life (min) | Inhibitors | Other substrates | Compounds not dechlorinated | N-terminal amino acid sequence | Reference(s) | ||
NRe | NR | NR | 1-Iodoethane, sulfite, dithionite, cyanide, azide | NR | TCE, 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE, VC | NR | 19 | ||
NR | NR | NR | 1-Iodopropane, N2O, sulfite | TCE | cis-1,2-DCE | GQESESAIVXFAVQXV | 42 | ||
8 | 42 | 120 | 1-Iodopropane, sulfite, cyanide, nitrite, N2O, EDTA, chlorinated methanes | trans-1,3-DCP, 2,3-DCP, 1,1,3-TCP | 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE, HCA, 1,1,1-TCA, 3-CB, 3,4-DCB, 4-CP | GVPGANAAEKEKNAA EIRQQFAMTAGS | 25-27 | ||
8.1 | NR | 280 | 1-Iodopropane | CT, HCA, 1,1,2,2-TeCA, 1,1,1,2-TeCA, 1,1,2-TCA, (1,1,1-TCA) | 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE | ADIVAPITETSEFPYKV DAK | 33, 34; this study | ||
7.2 | 50 | 50 | 1-Iodopropane, cyanide, azide, sulfite, EDTA | NR | CT, 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE | ADIVAPITETSEFPYKV DAK | 21, 22 | ||
NR | NR | NR | NR | NR | cis-1,2-DCE, chlorophenols | ADIVAPITEXTEFPYPV | 42 | ||
7.2 | 37 | 330 | 1-Iodopropane, sulfite | HCA, PCA, 1,1,2,2-TeCA, 1,1,1,2-TeCA | 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE, 1,1,1-TCA, 1,1,2-TCA | ADIVAPITETSEFPYKV DAK | 41 | ||
7.5 | 35 | 1,200 | 1-Iodopropane | 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE, 1,1,1-TCA, 1,1,2-TCA | VC | AEVYNKDGNKLDLYGK VDGLHYFSNDT | 29 | ||
NR | NR | NR | 1-Iodopropane, sulfite, dithionite, cyanide, azide, Cu2+, Zn2+ | 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE, (VC), (VB), 1,2-DCA, 1,2-DBA | PCE, 1,1,2,2-TeCA | KDVDDLLSAGKALEGD HANKVNNHPWW | 18, 19 |
Abbreviations for compounds: VC, vinyl chloride; DCP, dichloropropene; TCP, trichloropropene; CT, carbon tetrachloride; HCA, hexachloroethane; PCA, pentachloroethane; TeCA, tetrachloroethane; TCA, trichloroethane; DCA, dichloroethane; VB, vinyl bromide; DBA, dibromoethane; CB, chlorobenzoate; DCB, dichlorobenzoate; CP, chlorophenol.
m, membrane fraction; s, soluble fraction.
ND, not determined.
Determined by photo-reversible inhibition of the reduced enzyme by iodo-alkanes.
NR, not reported.
The corrinoid was determined by photo-reversible inhibition of the reduced enzyme by iodo-alkanes and was quantified by analysis of cobalt content and by extraction of the corrinoid from purified enzyme, followed by spectroscopic analysis. The 8Fe/8S was quantified by atomic absorption spectroscopy and by standard procedures for acid-labile sulfide.
The molecular mass depended on the detergent used; it was 164 kDa with Triton X-100 (micelle mass, 90 kDa), and it was 71 kDa with OGP (micelle mass, 8 kDa).
The corrinoid was determined by photo-reversible inhibition of the reduced enzyme by iodo-alkanes and by EPR spectroscopy and was quantified by analysis of cobalt content and by extraction of corrinoid from purified enzyme, followed by spectroscopic analysis. The presence of two [4Fe/4S] clusters was determined by EPR spectroscopy, and the iron and sulfur contents were quantified by atomic absorption spectroscopy and by standard procedures for acid-labile sulfide.