Question

Adults who are lactose intolerant cannot break down the disaccharide in milk products. To help digest dairy food, a product known as Lactaid can be added to milk and the milk then refrigerated for 24 hours. a. What enzyme is present in Lactaid, and what is the major class? b. What might happen to the enzyme if the Lactaid were stored at \(55^{\circ} \mathrm{C}\) ?

Short answer

a. Lactase, a hydrolase. b. The enzyme could denature at 55°C.

Step-by-step solution

Identify the enzyme in Lactaid

Lactaid contains an enzyme called lactase.

Determine the major class of the enzyme

Lactase belongs to the major class of enzymes known as hydrolases. Hydrolases catalyze the hydrolysis of various bonds.

Understand the impact of temperature on enzyme activity

Enzymes are sensitive to temperature changes. When stored at elevated temperatures, such as at 55°C, the enzyme could become denatured.

Describe enzyme denaturation

Denaturation is a process where the enzyme loses its three-dimensional structure and, as a result, its functionality. High temperatures can disrupt the hydrogen bonds and other forces holding the protein's structure together.

Conclude the effect of storing Lactaid at 55°C

If Lactaid were stored at 55°C, the lactase enzyme could denature, losing its ability to break down lactose in milk.

Key concepts

Lactose Intolerance

Lactose intolerance is a common condition where individuals have trouble digesting lactose, a sugar found in milk and dairy products. This occurs due to a deficiency in lactase, an enzyme needed to break down lactose into glucose and galactose. Symptoms often include:

• Abdominal pain
• Bloating
• Diarrhea
• Gas

Understanding your lactose intolerance can help you manage your diet and avoid discomfort. Products like Lactaid, which contain the lactase enzyme, can assist in digesting dairy more easily. They help break down lactose, making it digestible even for those who are lactose intolerant.

Enzyme Classification

Enzymes are biological molecules that accelerate chemical reactions in the body. They are classified into six major categories:

• Oxidoreductases
• Transferases
• Hydrolases
• Lyases
• Isomerases
• Ligases

Lactase, the enzyme in Lactaid, falls under the hydrolases category. Hydrolases specialize in breaking down compounds by adding water, a process called hydrolysis. Specifically, lactase catalyzes the hydrolysis of lactose into simpler sugars like glucose and galactose, aiding in their absorption and digestion.

Enzyme Denaturation

Enzyme denaturation is when an enzyme loses its natural structure due to external factors. This structural change often results in a loss of function because the specific shape of an enzyme's active site is essential for its activity. Factors causing denaturation include:

• High temperatures
• Extreme pH levels
• Chemical exposure

When lactase in Lactaid is denatured, its capacity to break down lactose diminishes. Denaturation primarily affects the amino acid bonds, disrupting the enzyme's shape and functionality. For lactase, this means it can no longer efficiently digest lactose, rendering the Lactaid ineffective.

Temperature Effects on Enzymes

Temperature plays a crucial role in enzyme activity. Each enzyme has an optimal temperature range where it functions best.
Exceeding this range can lead to denaturation. For lactase, optimal activity generally occurs at body temperature (around 37°C or 98.6°F). If stored at a temperature as high as 55°C, as mentioned in the exercise, the enzyme could become inactive. High temperatures disrupt:

• Hydrogen bonds
• Hydrophobic interactions
• Ionic bonds

This structural disruption means lactase loses its ability to interact with lactose, preventing the breakdown process. To preserve the activity of enzymes like lactase, it's recommended to store them within their stability range.