For measuring Hemicellulase activity (Xylanase assay), I used the procedure adapted from Bailey et al. (1992) using the Xylan as the substrate (1ml), DNS reagent (3ml), and 0.1Mcitrate phosphate buffer (0.9ml) + enzyme (0.1ml). So, after xylanase assay we need to calculate xylanase activity in the form of UI.
Hi there,
The basic to know is that 1IU corresponds to the apparition of 1µmole of product per minute. The xylanase assay with DNS is based on the colorimetric detection of reducing sugar due to xylanase activity. So the rate of the reaction is first expressed as variation of absorbance per time unit (you have to make sure that the rate of the reaction is constant upon the laps of time considered for calculation). Using Beer's law, the rate is converted into variation of concentration per time unit and then knowing the final sample volume (5mL I guess) and the possible dilution prior to absorbance measurement the rate is converted into mole/min. At last 0.1mL of enzyme has been used so activity might be expressed as mol/min/mL (by divinding the rate in mol/min by 0.1mL). If you want to express it as IU/min/mL then you have to multiply the result by 106 as 1mole is 106 µmoles.
Dear Sir ..you can see this publication
http://www.sciencedirect.com/science/article/pii/016816569290074J
https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Enzyme_Assay/xylanase.pdf
Firstly you need standard curve of your product and by using its equation you can know your enzyme uint
Thanks Dr. Mohamed Hassan, I did the standard curve and the determination of DO with equation of standard curve but I have issue with calculation after this step
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