the enzyme activity is separated and purified q sepharose phenyl sepharose hitrap blue and gel filtration chromatography columns can be used sequentially to separate the carbonyl reductase the size of the above protein is approximately 40 u02dc 42 kda fig2 as analyzed by running 12 sds polyacrylamide gel the active temperature and ph ranges were determined by measuring the activity of the enzyme against the substrate the active temperature is 25 u02dc 35 u00b0 c and preferably 30 u00b0 c the active ph is 6 5 u02dc 7 5 and preferably 6 8 the activity of the above protein at 30 u00b0 c and ph 6 8 is shown in fig4 as shown in fig3 kluyveromyces marxianus produces 4 different isomers 2s 3r 2r 3s 2r 3r and 2s 3s by reducing the substrate on the other hand carbonyl reductase purified according to the present invention from kluyveromyces marxianus produces asymmetric isomers 2s 3r and 2r 3r by reacting with the substrate as shown in fig4 it is distinctly different from the known enzymatic reaction of the yeast reductase which produces two asymmetric compounds 2r 3s and 2s 3s also the amount of the obtained protein in each column step and the carbonyl reductase activity of the protein are listed in table 1 the amount of the obtained protein in each column step was determined by bradford analysis method bradford m anal biochem.