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• Evan Walsh

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Determination of Enzyme Activity: Invertase assay 22/1/2019 Name: Evan Walsh Lab Partner’s Name: Shane Quinn Aims and Objectives The purpose of this experiment is to determine the rate of enzyme activity of invertase using the invertase assay. Introduction Invertase (Sucrase) is an enzyme that catalyses the hydrolysis of sucrose into its constituent monosaccharides, glucose and fructose. Since sucrose is not a reducing sugar, but glucose and fructose are, the rate of enzyme activity can be calculated using a standard curve. The rate of enzyme activity is calculated in international units (IU’s). IU is calculated as the µmoles of product formed per minute per ml of (undiluted) enzyme. A range of dilutions will be made in order to get an absorbance that can be read on the standard curve. Results Table 1. Absorbance results of dilutions

Dilutions 1/10 1/50 1/100 1/200

Absorbance 2.631 0.410 0.213 0.09

Graph 1. Standard Curve

Concentration VS Absorbance 0.9 0.8

Absorbance

0.7 0.6

0.5 0.4 0.3 0.2 0.1

0 0

500

1000

1500

2000

2500

Concentartion (µmoles/ml)

3000

3500

Calculations Absorbance at 1/50 dilution = 0.410 Concentration = 2000 µmoles/ml IU = 2000 x 25 ÷ 5 = 10000 IU = 10000 Discussion The Absorbance of the enzyme at 1/50 dilution was 0.410. Using the standard curve this meant the concentration of reducing sugars was 2000 µmoles/ml. When multiplied the amount of undiluted enzyme and divided by 5 to get the amount produced in one minute the final IU result was 10000. Conclusion The experiment should the IU of Invertase was 10000.