I have assayed cellulose activity, by DNS method, I got released reducing sugar in mg/ml for this. How do I calculate enzyme activity and express in IU?
First, convert the amount of reducing sugars from mg/mL to micromol/mL. Then multiply by your assay volume to find out how many micromoles of reducing sugars were released. Divide by the time of the assay and you will get the IU. One IU is defined as the amount of enzyme that releases one micromole of redicing sugar per minute in your reaction conditions.
Also remember that it is more common to express activities per weight of enzyme present in your experiment (i.e.: IU/mg of enzyme).
First, convert the amount of reducing sugars from mg/mL to micromol/mL. Then multiply by your assay volume to find out how many micromoles of reducing sugars were released. Divide by the time of the assay and you will get the IU. One IU is defined as the amount of enzyme that releases one micromole of redicing sugar per minute in your reaction conditions.
Also remember that it is more common to express activities per weight of enzyme present in your experiment (i.e.: IU/mg of enzyme).
for cellulase enzyme one IU is the amount of enzyme require to release one micromole of redicing sugar per minute in standard assay conditions.
The two above answers are correct, & I agree with what Sergio Navarrete Serradilla mentioned it is better to use the specific activity ( Activity /mg of protein ) rather than only the activity for comparison since usually there is variation in the protein concentrations.
Hi,
The answer of Sergio Navarrete Serradilla is correct. Try it.
Good Luck
I sending you cellulase activity paper find attachment.
Formula:
IU/ml = mg/ml x 1000 / Incubation time x volume of enzyme x molecular wt.
IU = amount of enzyme required to release 1 micromole of reducing sugars/min
So, first check the molecular weight of glucose, which is the monosaccharide unit for cellulose. Convert mg of sugars released to micromoles of reducing glucose equivalent released. Divide it by volume of enzyme and time of assay in minutes to get unit activity. The above formula is correct. Just an explanation for the same.
IU/ml = mg/ml x 1000 / Incubation time x volume of enzyme x molecular wt. of glucose
The reference have all conversions with formulae. hope u will be benefited. All d best.
Ghose, T.K. 1987. "Measurement of Cellulase Activities." Pure & Appl. Chem. 59: 257-268
The general equation could be that provided by Robert A. John in "Enzyme Assays: A practical approach", R. Eisenthal and M.J. Danson (Ed.), allowing to calculate micromols of product released per minute (Units of enzyme activity):
[(dA/dt)/e] x Vf x 1000 x (Vt/Vs), where dA/dt is the absorbance reading at the time defined for the assay (check the linear behavior of d[P]/dt), "e" is the molar extinction coefficient (mol L^-1). Concerning the volumes, Vs is the volume of enzyme solution (sample used in the assay), Vt is the total volume of the enzyme solution that you have and Vf the final volume of the assay mixture in the cuvette. All the volumes expressed in milliliters. The "1000" remains after the conversions from mol to micromol and liter to mL.
plz how to convert the amount of reducing sugars from mg/mL to micromol/mL
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