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Literature summary for 4.2.1.157 extracted from

  • Kim, J.; Darley, D.; Buckel, W.
    2-Hydroxyisocaproyl-CoA dehydratase and its activator from Clostridium difficile (2005), FEBS J., 272, 550-561.
    View publication on PubMed
Search for more literature for 4.2.1.157

Activating Compound

Activating Compound Comment Organism Structure
activator HadI the homodimeric activator is extremely oxygen-sensitive. Recombinant HadI activates the dehydratase in the presence of ATP, MgCl2 and a one-electron reducing agent titanium(III) citrate or dithionite Clostridioides difficile

Cloned(Commentary)

Cloned (Comment) Organism
the hadBC and hadI genes from Clostridium difficile are functionally expressed in Escherichia coli. They encode the 2-hydroxyisocaproyl-CoA dehydratase HadBC and its activator HadI Clostridioides difficile

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.05 0.08 (R)-2-hydroxy-4-methylpentanoyl-CoA pH 8.0, temperature not specified in the publication Clostridioides difficile

Metals/Ions

Metals/Ions Comment Organism Structure
Iron the enzyme contains 5.7 nonheme iron and 6.1 acid-labile sulfur, determined by chemical analysis Clostridioides difficile
Zn2+ besides varying amounts of zinc, other metal ions, particularly molybdenum, are not detected in the dehydratase Clostridioides difficile

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
42350
-
 1 * 46578 + 1 * 42350, calculated from sequence Clostridioides difficile
43000
-
 2 * 43000, SDS-PAGE Clostridioides difficile
46578
-
 1 * 46578 + 1 * 42350, calculated from sequence Clostridioides difficile
90000
-
 gel filtration Clostridioides difficile

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
(R)-2-hydroxy-4-methylpentanoyl-CoA Clostridioides difficile i.e. (R)-2-hydroxyisocaproyl-CoA. The enzyme is involved in the reductive branch of L-leucine fermentation 4-methylpent-2-enoyl-CoA + H2O i.e. isocaprenoyl-CoA ?

Organism

Organism UniProt Comment Textmining
Clostridioides difficile Q5U923 and Q5U924 hadC: Q5U923, hadB: Q5U924
-

Purification (Commentary)

Purification (Comment) Organism
-
 Clostridioides difficile

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
(R)-2-hydroxy-4-methylpentanoyl-CoA i.e. (R)-2-hydroxyisocaproyl-CoA. The enzyme is involved in the reductive branch of L-leucine fermentation Clostridioides difficile 4-methylpent-2-enoyl-CoA + H2O i.e. isocaprenoyl-CoA ?
(R)-2-hydroxy-4-methylpentanoyl-CoA i.e. (R)-2-hydroxyisocaproyl-CoA. The enzyme is specific for the R-isomer. The reduced activator transfers one electron to the dehydratase concomitant with hydrolysis of ATP. The activated dehydratase is separated from the activator and ATP. It catalyzes about 10000 dehydration turnovers until the enzyme becomes inactive. Adding activator, ATP, MgCl2, dithionite and dithioerythritol reactivates the enzyme. The enzymatic elimination of H2O probably occurs in syn-fashion. In assays using (E)-isocaprenoyl-CoA as substrate, no activity can be observed suggesting that the dehydration is irreversible under these conditions or the Z-isomer is the correct product Clostridioides difficile 4-methylpent-2-enoyl-CoA + H2O i.e. isocaprenoyl-CoA ?

Subunits

Subunits Comment Organism
heterodimer 2 * 43000, SDS-PAGE Clostridioides difficile
heterodimer 1 * 46578 + 1 * 42350, calculated from sequence Clostridioides difficile

Synonyms

Synonyms Comment Organism
2-hydroxyisocaproyl-CoA dehydratase
-
 Clostridioides difficile
HadBC
-
 Clostridioides difficile

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8
-
 assay at Clostridioides difficile

General Information

General Information Comment Organism
metabolism the enzyme is involved in L-leucine fermentation Clostridioides difficile