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Ch.16 Amino Acids, Proteins, and Enzymes
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 16, Problem 56b

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.
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b. What might happen to the enzyme if the Lactaid were stored at 55 °C?

Verified step by step guidance
1
Understand the role of enzymes: Enzymes are biological catalysts that speed up chemical reactions. They are proteins and have a specific three-dimensional structure that is crucial for their function.
Recognize the effect of temperature on enzymes: Enzymes have an optimal temperature range in which they function most effectively. For most enzymes in the human body, this range is around 37 °C (body temperature).
Consider the impact of high temperatures: At temperatures significantly above the optimal range, such as 55 °C, the enzyme's structure can become denatured. Denaturation involves the breaking of bonds that maintain the enzyme's shape, causing it to lose its functionality.
Relate this to the problem: If Lactaid (which contains the enzyme lactase) is stored at 55 °C, the enzyme may denature, rendering it unable to break down lactose effectively. This would make the product ineffective for lactose-intolerant individuals.
Conclude the importance of proper storage: To preserve the enzyme's activity, Lactaid should be stored at a temperature within its recommended range, typically refrigeration (around 4 °C), to prevent denaturation and maintain its effectiveness.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Lactase Enzyme Function

Lactase is an enzyme that breaks down lactose, a disaccharide found in milk, into glucose and galactose, which can be easily absorbed by the body. In individuals who are lactose intolerant, the body produces insufficient lactase, leading to digestive issues when consuming dairy products. Understanding the role of lactase is crucial for comprehending how Lactaid aids in digestion.
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Enzyme Stability and Temperature

Enzymes are proteins that function optimally within a specific temperature range. Storing Lactaid at 55 °C may denature the lactase enzyme, altering its structure and rendering it ineffective. This concept highlights the importance of temperature control in maintaining enzyme activity and effectiveness in digestive aids.
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Impact of Denaturation

Denaturation refers to the process where an enzyme's three-dimensional structure is altered, often due to extreme temperatures or pH levels, leading to a loss of function. If Lactaid is stored at an inappropriate temperature, the lactase may denature, preventing it from breaking down lactose and thus failing to alleviate lactose intolerance symptoms.
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Related Practice
Textbook Question

Ethylene glycol (HO—CH2—CH2—OH) is a major component of antifreeze. If ingested, it is first converted to HOOC—CHO (oxoethanoic acid) and then to HOOC—COOH (oxalic acid), which is toxic.

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a. What class of enzyme catalyzes the reactions described?

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Textbook Question

Ethylene glycol (HO—CH2—CH2—OH) is a major component of antifreeze. If ingested, it is first converted to HOOC—CHO (oxoethanoic acid) and then to HOOC—COOH (oxalic acid), which is toxic.

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b. The treatment for the ingestion of ethylene glycol is an intravenous solution of ethanol. How might this help prevent toxic levels of oxalic acid in the body?

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Textbook 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.

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a. What enzyme is present in Lactaid, and what is the major class of this enzyme?

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Textbook Question

Fresh pineapple contains the enzyme bromelain that hydrolyzes peptide bonds in proteins.

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a. The directions for a gelatin (protein) dessert say not to add fresh pineapple. However, canned pineapple where pineapple is heated to high temperatures can be added. Why?

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Textbook Question

Fresh pineapple contains the enzyme bromelain that hydrolyzes peptide bonds in proteins.

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b. Fresh pineapple is used in a marinade to tenderize tough meat. Why?

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Textbook Question

Identify the amino acids and type of interaction that occurs between the following R groups in tertiary protein structures:

a.

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