Polypeptide having esterase activity and recombinant esterase and use thereof

1. A method of resolving stereoselectively racemic 2-alkyl-5-halopent-4-ene-carboxylic esters of the formula (I)

in which R is a C 1 -C 6 -alkyl radical, R 1 is C 1 -C 4 -alkyl and X is chlorine, bromine or iodine, comprising contacting a racemic ester of formula (I) with a polypeptide or recombinant protein having esterase activity and exhibiting an amino acid sequence that is at least 98% identical to the amino acid sequence of SEQ. ID. No. 1.

2. A method for preparing enantiomerically enriched 2-alkyl-5-halopent-4-enecarboxylic acids or esters thereof of the formula (II)

in which R is a C 1 -C 6 -alkyl radical, A is equal to H, R 1 , where R 1 may be C 1 -C 4 -alkyl, or R 2 , where R 2 is an alkyl group, but is not equal to R 1 , and X is chlorine, bromine or iodine, the method comprising converting a mixture of enantiomers of a 2-alkyl-5-halopent-4-enecarboxylic ester of the formula (I)

in which R, R 1 and X are as defined above,

using a polypeptide or a recombinant esterase having esterase activity and exhibiting an amino acid sequence that is at least 98% identical to the amino acid sequence of SEQ. ID. No. 1 in the presence of water or an alcohol of the formula R 2 OH, where R 2 is an alkyl group which is not equal to R 1 , as nucleophile, and isolating

a) either the remaining enantiomerically enriched 2-alkyl-5-halopent-4-enecarboxylic ester of the formula (II) with A equal to R 1 or

b) if an alcohol is employed as nucleophile, the resulting enantiomerically enriched 2-alkyl-5-halopent-4-enecarboxylic ester of the formula (II) with A equal to R 2 or

c) if water is employed as nucleophile, the resulting 2-alkyl-5-halopent-4-enecarboxylic acid of the formula (II) with A equal to H.