Studies On Optimization, Preparation And Enzyme Catalytic Reaction Of Lactate Dehydrogenase By Lactobacillus Plantarum

Lactate dehydrogenase (EC1.1.1.27;LDH) is important glycolytic enzymes that reversiblycatalyse the conversion of pyruvate to lactate. The enzymes are widely present in animals, bacteriaand also in plants. With the aim of exploitation and application of LDH, the research mainlyfocused on the culture conditions of Lactobacillus plantarum , preparation of lactatedehydrogenase from Lactobacillus plantarum, enzyme catalytic reaction conditions andapplication。With the aim of improving the cell concentration and the special activity, the culture conditionsof Lactobacillus plantarum were studied. It was shown that Tween 80,sodium chloride and tomatojuice had significant role on the biomass and specific activity, and the optimal concentration ofTween 80,sodium chloride and tomato juice was 3ml/L,10g/L～15 g/L and 15 ml/L. At the sametime, vitamin C and lycopene showed significant role on Lactobacillus plantarum. The cellconcentration and the special activity were improved respectively by 94% and 14% with partitionfermentation.The preparation of LDH from a Strain Lactobacillus plantarum was designed. LDH could beprepared by DEAE Sepharose F.F. ion exchange chromatography ,Phenyl Sepharose 6 F.F.hydrophobic chromatography and Sephadex G-25 Fine. The final specific activity of LDH could beup to 1025.1 U/mg and purity was 88%. 28.7-fold purification was obtained with 67.9%enzymatic activity recovery. The molecular weight of LDH estimated by HPLC was 80 kD, and themolecular weight of each subunit shown on SDS-PAGE could be 39kD. At last,The enzymecatalytic reaction conditions and application of LDH were studied.