Structure and function of a novel fungal enzyme, lactonohydrolase, and its application to optical resolution of pantolactone

真菌内酯水解酶可催化d -泛酰基内酯分子内酯键的立体特异性水解，可用于外消旋泛酰基内酯的光学拆分。通过对多种微生物的筛选，发现该立体特异性水解反应在镰刀菌属、赤霉素属和圆柱碳属的几种丝状真菌中均具有高活性。尖孢镰刀菌AKU 3702具有较高的酶产率，含有该酶的细胞可重复用于该酶的水解反应。在3%甘油、0.5%多肽、0.5%酵母提取物和0.5%玉米浸泡液中培养的真菌菌丝体，在pH 6.0条件下水解46.0% （700 mg/ml）的泛酸，形成的泛酸光学纯度为96%以上的对映异构体。

A fungal lactonohydrolase catalyzes the stereospecific hydrolysis of the intramolecular ester bond of D-pantoyl lactone and is useful for optical resolution of racemic pantoyl lactone. High activity of this stereospecific hydrolysis reaction was found in several filamentous fungi belonging to the genera Fusarium, Gibberella and Cylindrocarpon through the screening in a variety of microorganisms. Fusarium oxysporum AKU 3702 showed high productivity of the enzyme and the cells containing the enzyme could be used repeatedly for this hydrolysis reaction. On incubation with the mycelia of this fungus, which had been cultivated in 3% glycerol, 0.5% Polypepton, 0.5% yeast extract and 0.5% corn steep liquor, pH 6.0,46.0% of the recemic pantoyl lactone (700 mg/ml) was hydrolyzed and the optical purity of the pantoic acid formed was 96% enantiomeric excess for the D-isomer.