IUBMB Enzyme Nomenclature


Accepted name: aliphatic (R)-hydroxynitrile lyase

Reaction: (2R)-2-hydroxy-2-methylbutanenitrile = cyanide + butan-2-one

Other name(s): (R)-HNL; (R)-oxynitrilase; (R)-hydroxynitrile lyase; LuHNL

Systematic name: (2R)-2-hydroxy-2-methylbutanenitrile butan-2-one-lyase (cyanide forming)

Comments: The enzyme contains Zn2+ [1]. The enzyme catalyses the stereoselective synthesis of aliphatic (R)-cyanohydrins [1]. No activity towards mandelonitrile and 4-hydroxymandelonitrile [5]. Natural substrates for the (R)-oxynitrilase from Linum usitatissimum are acetone and butan-2-one, which are the building blocks of the cyanogen glycosides in Linum, linamarin and lotaustralin, or linustatin and neolinustatin, respectively [4].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Trummler, K., Roos, J., Schwaneberg, U., Effenberger, F., Förster, S., Pfizenmaier, K., Wajant, H. Expression of the Zn2+-containing hydroxynitrile lyase from flax (Linum usitatissimum) in Pichia pastoris - utilization of the recombinant enzyme for enzymatic analysis and site-directed mutagenesis. Plant Sci. 139 (1998) 19-27.

2. Trummler, K. and Wajant, H. Molecular cloning of acetone cyanohydrin lyase from flax (Linum usitatissimum). Definition of a novel class of hydroxynitrile lyases. J. Biol. Chem. 272 (1997) 4770-4774. [PMID: 9030531]

3. Albrecht, J., Jansen, I.and Kula, M.R. Improved purification of an (R)-oxynitrilase from Linum usitatissimum (flax) and investigation of the substrate range. Biotechnol. Appl. Biochem. 17 (1993) 191-203.

4. Xu, L.-L., Singh, B.K. and Conn, E.E. Purification and characterization of acetone cyanohydrin lyase from Linum usitatissimum. Arch. Biochem. Biophys. 263 (1988) 256-263. [PMID: 3377504]

5. Cabirol, F.L., Tan, P.L., Tay, B., Cheng, S., Hanefeld, U. and Sheldon, R.A. Linum usitatissimum hydroxynitrile lyase cross-linked enzyme aggregates: a recyclable enantioselective catalyst. Adv. Synth. Catal. 350 (2008) 2329-2338.

6. Breithaupt, H., Pohl, M., Bönigk, W., Heim, P., Schimz, K.-L. and Kula, M.-R. Cloning and expression of (R)-hydroxynitrile lyase from Linum usitatissimum (flax). J. Mol. Catal. B 6 (1999) 315-332.

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