Question

What is the name of the class of enzymes that would catalyze each of the following reactions? a. hydrolysis of sucrose b. addition of oxygen c. converting glucose \(\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)\) to fructose \(\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)\) d. moving an amino group from one molecule to another

Short answer

a. hydrolase, b. oxidase, c. isomerase, d. transferase (aminotransferase)

Step-by-step solution

Identify the type of reaction for hydrolysis of sucrose

In a hydrolysis reaction, a water molecule is used to break a bond in a larger molecule. The enzyme that catalyzes the hydrolysis of sucrose is a hydrolase.

Identify the enzyme for the addition of oxygen

Enzymes that catalyze the addition of oxygen to a substrate are called oxidases or oxygenases. These enzymes are involved in oxidation reactions. For this reaction, the enzyme is an oxidase.

Identify the enzyme for converting glucose to fructose

The conversion of glucose to fructose involves the rearrangement of atoms within the molecule, categorized as an isomerization reaction. The enzyme that catalyzes this type of reaction is an isomerase.

Identify the enzyme for moving an amino group from one molecule to another

The transfer of an amino group from one molecule to another is catalyzed by a class of enzymes known as transferases, specifically aminotransferases.

Key concepts

hydrolase

Hydrolases are enzymes that facilitate hydrolysis reactions. In these reactions, a water molecule breaks a bond within a compound. For instance, the hydrolysis of sucrose splits sucrose into glucose and fructose. Hydrolases are crucial for various biological processes, such as digestion. They help break down complex molecules, making nutrients available for absorption and utilization by the body. Examples of hydrolases include amylase, which breaks down starches, and lipase, which breaks down fats.

oxidase

Oxidases are enzymes involved in oxidation-reduction reactions. These enzymes facilitate the transfer of electrons from one molecule to oxygen, adding oxygen to the substrate. Oxidases play an essential role in cellular respiration and detoxification processes. For example, cytochrome oxidase acts in the electron transport chain, essential for energy production in cells. Other oxidases, like alcohol oxidase, help convert ethanol into acetaldehyde, involved in alcohol metabolism.

isomerase

Isomerases are enzymes that catalyze the rearrangement of atoms within a molecule, converting it into a different isomer. One prominent example is the conversion of glucose to fructose. Such changes enable the molecule to participate in varied metabolic pathways. Isomerases are critical for cellular functions like glycolysis and biosynthesis. They ensure that molecules are in the correct form needed for subsequent chemical reactions. Examples include phosphoglucoisomerase, involved in glycolysis, and triosephosphate isomerase, which catalyzes steps in carbohydrate metabolism.

aminotransferase

Aminotransferases, also known as transaminases, are enzymes that transfer amino groups between molecules. This reaction is vital for the synthesis and degradation of amino acids, the building blocks of proteins. By moving an amino group from one molecule to another, aminotransferases help maintain the balance of amino acids in the body. They are indispensable for processes like the urea cycle and gluconeogenesis. Two main examples include alanine aminotransferase (ALT) and aspartate aminotransferase (AST), both of which are used in clinical settings to assess liver function.