Essay by brownie231 November 2014

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Lactase Enzyme Lab


This lab will examine the specificity of an enzyme (lactase) to a specific substrate (lactose). Students will observe the actions of the enzyme and how shape is important to enzyme reactions. Students will also observe what will happen when the enzyme is denatured.


Lactase tablets-these can be bought at grocery and drug stores

15ml milk- any milk will do

Water-used for dissolving the lactase tablet, dissolving the sucrose and boiling the lactase

Sucrose-5g per group

100ml graduated cylinder

10ml graduated cylinder

three 400ml beakers- used for dissolving the lactase tablet, dissolving the sucrose and boiling the lactase

5 test tubes- these tubes hold the different solution mixtures

test tube rack

marking pencil


hot plate with a pyrex test tube fore denaturing the enzyme

glucose test strips- these can be found in drugstores

stirring rod


Lactose, the sugar found in milk, is a disaccharide composed of glucose and galactose (both six sided sugars).

Sucrose, ordinary table sugar, is also a disaccharide composed of fructose and glucose, Glucose is a six-sided sugar and fructose is a five-sided sugar.

Lactase is an enzyme that breaks lactose down into galactose and glucose. Lactase can be purchased in pill form by people who are lactose intolerant. These people lack the enzyme, lactase, and cannot break down the sugar lactose into its component parts.

Although lactose is similar to sucrose, lactase will break down only lactose because of the shape of the sugar.

In this lab, you will see lactase break lactose down into galactose and glucose. You will also observe what happens if the shape of lactase is changed due to heating.


Solution preparation

Enzyme solution: Add one lactase tablet to two hundred milliliters of water. Stir until the tablet has dissolved.