Enzyme kinetic measurements performed on a BMG LABTECH microplate reader

Franka Ganske BMG LABTECH 04/2009

Esterases catalyze hydrolysis reactions by converting esters into an acid and an alcohol using water as nucleophil. They are often used as biocatalysts to produce optically pure compounds. Esterases differ in their affinity to specific substrates and this affinity is represented by the Michaelis-Menten constant Km. BMG LABTECH has developed a new evaluation software feature able to calculate the Km value as well as the maximal velocity (Vmax) from an enzymatic kinetic measurement.


As a model reaction, the p-nitrophenyl acetate (pNPA) assay was performed on a BMG LABTECH microplate reader. The enzyme hydrolyzes the acetate ester with the help of water. The products are acetic acid and p-nitrophenol (pNP), the latter showing an absorption maximum at about 405 nm.


The software feature for enzyme kinetic offers fast and easy calculation of Km and Vmax. Available plots are the common Michaelis-Menten, Lineweaver-Burk, Eadie-Hofstee, Scatchard and Hanes kinetic fits.

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