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# How to Calculate Nanokatals Per Gram

Updated February 21, 2017

A nanokatal per gram refers to the catalytic activity of an enzyme. To determine this catalytic activity, the rate of the conversion and experiment parameters must be set. A katal per gram of trypsin enzyme is the amount of trypsin needed to catalyse bonds when certain conditions are met. When the conditions change, the number of bonds that are catalysed will change. It is easiest to calculate the enzyme unit and then convert this to nanokatals per gram.

Calculate the enzyme unit. This unit is found by multiplying the rate of reaction by the enzyme concentration. The rate of reaction units are (umol/ml)/min and enzyme concentration is normally mg/ml.

Enzyme Unit (U) = rate of reaction x enzyme concentration

Calculate the rate of reaction from the performed enzymatic assay. Enzymatic assays work by having a colour change when the product is formed by the enzyme over time. The absorbance is measured by a spectrophotometer.

(Finishing absorbance - starting absorbance)/time of reaction = enzyme rate of change (umol/ml)/min

Convert the enzyme units to nanokatals. The conversion rate is 1 U = 16.67 nanokatal.

Enzyme Units * (16.67 nanokatal/1 enzyme unit) = nanokatals.

Determine the nanokatals per gram by dividing the calculated nanokatals by the weight of the enzyme used.

#### Things You'll Need

• Calculator
• Enzymatic assay kit (optional)