Enzyme Activity- Lactase

532 Words3 Pages
Lactase Buffer solutions 4,7,9 Enzymes are organic catalysts that control the rate of chemical reactions in cells while not being permanently altered themselves. In general, enzymes speed up the rate of reaction by lowering the activation energy required to start reactions. Lactase is an enzyme used by the body to hydrolyze lactose, a disaccharide unique to mammalian milk, into the monosaccharaides, glucose and galactose. Lactose has been shown to aid in the absorption of several minerals, including calcium, magnesium, and zinc. . Experiment #2: Determining Effect of pH on Lactase Activity will involve students testing a range of different pH solutions mixed with cow milk to see if there is a change in the lactase activity. 
Access student prior knowledge on what conditions most affects enzyme activity (pH and temperature). Discuss what neutral, acidic, and basic (or alkaline) pH values are and where they are found in the pH range (0-14). Review the effect of pH on enzyme function. Students should understand that enzymes function best at specific pH levels (which vary depending on the enzyme). Non-optimal pH levels can affect the shape of the enzyme, thereby decreasing its effectiveness as a catalyst. Extreme pH levels can permanently denature the enzyme protein, whereas less extreme pH conditions may only temporarily alter . Lactase is effective at pH 2 – 7 (including dH2O) and therefore breaks down the lactose sugar in milk into glucose and galactose. As a result, the test strips will turn a shade of brown. . Lactase is not effective at pH 10 – 12. At the high pHs, the enzyme lactase is denatured and is no longer able to break down the sugar lactose in milk. Therefore, no glucose is present and the test strips remain blue. . The optimum range for the activity of lactase would be considered pH 2-7. The water control tube should match the tube with a
Open Document