Looking into Lactase is an activity developed by Learning Undefeated for the exploration of enzymatic activity by investigating the mechanism behind lactose intolerance.
Lactase d eficiency, also known as lactose intolerance, is a condition caused by an absence of the enzyme lactase, a digestive enzyme found in the human body. Since the human body can’t absorb lactose it needs to be broken down by lactase into its two monosaccharide products, glucose and galactose. Like most other enzymes, lactase is specific to just one substrate, in this case, the sugar lactose. Those who are lactose intolerant seek treatment through medications that contain lactase as an active ingredient.
Enzymes are proteins that catalyze chemical reactions by lowering the reaction’s activation energy. Every enzyme has an active site that binds to another molecule called the substrate. Once bound to the substrate, an enzyme can catalyze a reaction up to 10 billion times faster than the comparable, non-catalyzed reaction. Enzymes are not consumed in the reaction and can bind to an infinite amount of substrates.
Students will be able to
Illustrate how amino acids interact to create a protein
Identify an enzyme’s specific substrate
Differentiate between three different milk types based upon their sugar content
Explain how pH effects enzyme activity
Infer how enzyme activity relates to human physiology
Standards Alignments + Connections
MS-LS1-7: Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism.
HS-LS1-1: Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells.
BIOL.9C: identify and investigate the role of enzymes
LS.11C: environmental factors and genetic variation, influence survivability and diversity of organisms
BIO.2C: enzymes have a role in biochemical processes
What pH levels do you predict are found in the human body?
You are working in the quality control department of a local bioscience company that produces a lactase enzyme product used to treat lactose intolerance. It is your job to determine the optimal pH of the lactase product by testing the enzyme’s activity in cow’s milk at different pH levels. Unfortunately, due to a mistake in shipping, the labels were removed from the research lab’s milk supply. You know that the lab carries cow, rice, and soy milk, but you don’t know which is which. Before you can test the lactase activity at different pH levels, you must first identify which sample is cow’s milk, by using a special property of enzymes called “specificity.” Lactase specificity describes the fact that the lactase enzyme will break down lactose but no other disaccharide substrate.
For further information on enzymatic activity and lactase deficiency, visit: https://bit.ly/2rbLdWY
Additional Resources
NIH/NIDDK
Read about the causes of lactose intolerance and how it is diagnosed
Enzyme Resources
Learn about how enzymes work, how they are named, how they are affected by temperature and pH, and more
Students investigate the enzyme lactase and use the enzyme to help them identify the sugars that are present in three milk samples: rice milk, soy milk, and cow’s milk.