What type of reaction is primarily catalyzed by the enzyme lactase?

• A. Oxidation
• B. Hydrolysis
• C. Condensation
• D. Transamination

Answer: (B)

Lactase is an enzyme that catalyzes the hydrolysis of lactose, which is a disaccharide sugar found in milk. In this reaction, lactase breaks down lactose into its component monosaccharides, glucose and galactose, by adding water. This type of reaction, involving the enzymatic addition of water to cleave bonds, characterizes hydrolysis.

Hydrolysis is essential for digestion, as it allows for the breakdown of complex sugars into simpler sugars that can be absorbed by the body. The specific mechanism by which lactase acts showcases the importance of water in the process.

In contrast, oxidation refers to the loss of electrons or an increase in oxidation state, which does not apply to the function of lactase. Condensation involves the joining of two molecules with the release of water, again opposite to what lactase does. Transamination involves the transfer of an amino group from one molecule to another, which is also not relevant to the action of lactase. Thus, the action of lactase primarily exemplifies hydrolysis, making it the correct answer.