In enzymology, an acetylene hydratase (EC is a rare example of an enzyme containing tungsten. It catalyzes the hydration of acetylene to give acetaldehyde:[1]

Acetylene hydratase
EC number4.2.1.112
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
C2H2 + H2O → CH3CHO

The W centre is bound to two molybdopterin cofactors.[2] The mechanism is thought to involve attachment of acetylene to the metal followed by nucleophilic attack of water.[3]

This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is acetaldehyde hydro-lyase (acetylene-forming). Other names in common use include AH, and acetaldehyde hydro-lyase. Acetylene hydratase participates in tetrachloroethene degradation.


  1. ^ Rosner BM, Schink B (1995). "Purification and characterization of acetylene hydratase of Pelobacter acetylenicus, a tungsten iron-sulfur protein". J. Bacteriol. 177 (20): 5767–72. PMC 177396. PMID 7592321.
  2. ^ ten Brink, Felix (2014). "Chapter 2. Living on acetylene. A Primordial Energy Source". In Peter M.H. Kroneck and Martha E. Sosa Torres. The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment. Metal Ions in Life Sciences. 14. Springer. pp. 1–14. doi:10.1007/978-94-017-9269-1_2.
  3. ^ Einsle O; Ullmann, GM; Messerschmidt, A; Schink, B; Kroneck, PM; Einsle, O (2007). "Structure of the non-redox-active tungsten/[4Fe:4S] enzyme acetylene hydratase" (PDF). Proc. Natl. Acad. Sci. U.S.A. 104 (9): 3073–7. doi:10.1073/pnas.0610407104. PMC 1805521. PMID 17360611.