Enzymatic Activity of LDH

Students should prepare three stock solutions of pyruvate 150, 30, and 6 mM. 16.5 mg of pyruvate (MW = 110) dissolved in 1 ml of phosphate buffer, pH 7.5, yields a solution of 150 mM. Dilution of this solution five times yields a stock solution of 30 mM, and its dilution 25 times yields a stock solution equal to 6 mM. 

In a test tube, add 170 pi of the NADH stock solution, 100 pi of the 30 mM pyruvate stock solution, the appropriate volume of enzyme and then make up the quantity to 3 ml with phosphate buffer. Mix slowly then measure the variation of absorbance at 340 nm for 2 min. Calculate from the data obtained the specific enzyme activity. 

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The production of a variety of chemicals has been engineered by metabolic pathway engineering. Lactic acid production is dependent on lactate dehydrogenase (LDH) activities present in LAB. The lactic acid stereoisomerism is, in general, controlled by the enzymatic activity of LDH-L or LDH-D, although, in some cases, lactate... 

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