反应详情

Burkholderia caryophylli Lu681 (or other strains from Tab. 1) were grown in 25 ml of complex medium (for example HFP=1% peptone, 1% tryptone, 0.5% yeast extract, 0.3% NaCL) for 1 to 3 days, harvested, washed in Tris-HCl buffer (50 mM, pH 7.0) and resuspended (5 ml of 50 mM Tris/HCl, pH 7.0) and incubated with 50 mM ketopantolactone at 30° C. for 3 h. After removal of the cells, the concentrations of ketopantolactone, ketopantoic acid, D,L-pantolactone, D,L-, D-, and L-pantoic acid were determined by HPLC analysis (Tab. 1a). All the listed strains apart from Beauveria amorpha Lu7953 were able to reduce to pantoic acid the ketopantoic acid resulting from spontaneous hydrolysis of ketopantolactone. Since, however, D-pantoic acid was formed with all the strains instead of the L-pantoic acid described in Example 1, the conversion of pantolactone to L-pantoic acid cannot be produced by an oxidation-reduction process (via ketopantolactone and ketopantoic acid). No dependence of the L-pantolactone hydrolysis on cofactors was found in the dialyzed crude extract from Lu681 or Lu5351 and on use of the purified enzymes from Lu681 and Lu5351 either. The enzymatic activity can thus be attributed to a hydrolytic enzyme.