Catalyst and use thereof

1. A method of reducing an ethylene group in an unsaturated substrate, the method comprising

contacting the substrate with a catalyst, optionally in the presence of a co-substrate, thereby to generate a reduced substrate, wherein the catalyst is a polypeptide comprising an amino acid sequence having at least 95% identity to SEQ ID NO: 7, wherein the substrate concentration is 50 mM to 1500 mM, and wherein the ethylene group in the unsaturated substrate is conjugated to an aldehyde, a ketone carbonyl, a carboxy group, an alkoxy carbonyl group, an amido group, or a nitro group.

2. The method of claim 1 , wherein the substrate concentration is at least 100 mM.

3. The method of claim 2 , wherein the substrate concentration is at least 300 mM.

4. The method of claim 1 , wherein the catalyst is a polypeptide comprising an amino acid sequence having at least 98% identity to SEQ ID NO: 7.

5. The method of claim 3 , wherein the catalyst is a polypeptide comprising or consisting of the amino acid sequence of SEQ ID NO: 7.

6. The method of claim 1 , wherein the ethylene group is α,β to an acyl, carboxy, acyloxy, acylamino nitro or nitrile group.

7. The method of claim 1 , wherein the substrate is a compound of formula (I):

wherein:

—R 1 is acyl, carboxy, acyloxy, nitro, acylamino, or nitrile;

—R 2 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, amino, hydroxyl, or oxy, and optionally further amido;

—R 3 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, amino, hydroxyl, oxy, carboxy, acyloxy, nitrile, or acylamino,

or where —R 1 is acyl, acyloxy or acylamino, and

—R 1 and —R 2 form a ring containing the acyl, acyloxy or acylamino group or

—R 1 and —R 3 form a ring containing the acyl, acyloxy or acylamino group; and

—R 4 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, amino, hydroxyl, oxy, carboxy, acyloxy, nitrile and acylamino,

and each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, or aryl group is optionally substituted;

or —R 2 and —R 4 together form an unsubstituted or substituted ring.

8. The method of claim 1 wherein a co-substrate is a cofactor.

9. The method of claim 8 , wherein the cofactor is NADH.

10. The method of claim 1 , wherein the catalyst is provided by a kit comprising a reduction catalyst and one or more other catalysts, wherein the reduction catalyst is a polypeptide comprising an amino acid sequence having at least 95% identity to SEQ ID NO: 7.

11. The method of claim 1 , wherein the catalyst is provided by a catalyst preparation comprising a catalyst which is a polypeptide comprising an amino acid sequence having at least 95% identity to SEQ ID NO: 7, and wherein the amount of catalyst in the catalyst preparation is at least about 0.25 U of the catalyst per mg of the catalyst preparation.

12. The method of claim 1 , wherein the catalyst is encoded by a nucleic acid comprising a nucleic acid sequence having at least 95% sequence identity to the sequence of SEQ ID NO:8, wherein the nucleic acid encodes a polypeptide comprising an amino acid sequence having at least 95% identity to SEQ ID NO: 7.

13. The method of claim 1 , wherein the catalyst is provided by a vector comprising the nucleic acid defined in claim 12 .

14. The method of claim 1 , wherein the catalyst is provided by a host cell comprising the nucleic acid defined in claim 12 .

15. The method of claim 1 , wherein the catalyst is capable of reducing a caron-carbon double bond.

16. The method according to claim 10 , wherein the reduction catalyst is a polypeptide comprising an amino acid sequence having at least 98% identity to SEQ ID NO: 7.

17. The method according to claim 11 , polypeptide comprises an amino acid sequence having at least 98% identity to SEQ ID NO: 7.

18. The method according to claim 12 , wherein the nucleic acid encodes a polypeptide comprising an amino acid sequence having at least 98% identity to SEQ ID NO: 7.