The Two Monosaccharides Produced by Sucrase Acting on Sucrose

December 12, 2025 •

2 min read

Sucrose, commonly known as table sugar, is a disaccharide made up of two simpler sugar units. The human body cannot absorb this larger sugar directly, so it relies on a specific enzyme, sucrase, to break it down into its smaller, usable components during digestion.

Quick Summary

Sucrase breaks down the disaccharide sucrose into its two component monosaccharides, glucose and fructose, through a process called hydrolysis.

Key Points

Sucrase and Sucrose: The enzyme sucrase acts specifically on the disaccharide sucrose to break it down into two monosaccharides.
Glucose and Fructose: The two resulting monosaccharides produced from the hydrolysis of sucrose are glucose and fructose.
Hydrolysis Explained: This breakdown process, called hydrolysis, involves using a water molecule to cleave the glycosidic bond connecting the two sugar units.
Site of Action: In humans, the sucrase enzyme is located on the brush border of the small intestine, facilitating the final stage of sucrose digestion.
Energy Metabolism: Once broken down, glucose is readily absorbed and used for cellular energy, while fructose is metabolized primarily in the liver.
Sucrase Deficiency: A lack of functional sucrase can lead to sucrose intolerance, causing gastrointestinal distress as undigested sucrose is fermented by gut bacteria.

The Sucrase-Sucrose Reaction: Producing Glucose and Fructose

When the enzyme sucrase acts on the disaccharide sucrose, it produces two distinct monosaccharides: glucose and fructose. This critical biochemical process, known as hydrolysis, occurs primarily in the small intestine and is the final stage of sucrose digestion in humans. By breaking the chemical bond linking the two sugar units, sucrase makes the energy contained within sucrose available for the body to use.

What is Sucrose?

Sucrose, a disaccharide sugar, is composed of one molecule of glucose and one molecule of fructose joined together. It is the form of sugar most commonly used as a sweetener in foods and drinks.

The Role of Sucrase

Sucrase is an enzyme that facilitates the hydrolysis of sucrose. In humans, it is located on the brush border of the villi in the small intestine. This strategic location ensures that sucrose is efficiently cleaved into its constituent monosaccharides right before absorption. Without sufficient sucrase, sucrose cannot be properly digested, leading to uncomfortable gastrointestinal symptoms.

How Hydrolysis Works

The process of hydrolysis is a chemical reaction in which a molecule is broken down by the addition of water. For sucrase and sucrose, this involves:

Substrate Binding: Sucrose binds to sucrase.
Catalysis: The enzyme facilitates the use of a water molecule to break the bond between glucose and fructose.
Product Release: Glucose and fructose are released. The enzyme is then ready for another reaction.

Monosaccharides Explained

Once freed from the sucrose molecule, glucose and fructose have different fates and functions within the body.

Glucose: The Body's Primary Energy Source

Glucose is the body's preferred source of energy for cells. Insulin helps move glucose from the blood into cells for energy or storage.

Fructose: The Fruit Sugar

Fructose is found naturally in many fruits and vegetables. It must be metabolized by the liver, which converts it into glucose or stores it as fat. It is the sweetest natural sugar.

Comparing the Sugars: Sucrose, Glucose, and Fructose


Feature	Sucrose	Glucose	Fructose
Classification	Disaccharide	Monosaccharide	Monosaccharide
Component Sugars	Glucose + Fructose	Single Unit	Single Unit
Digestion	Needs to be broken down by sucrase	Absorbed directly	Absorbed directly, metabolized by liver
Energy Source	Converted to monosaccharides for energy	Primary energy source for cells	Converted to glucose or fat by liver
Found In	Table sugar, candy, baked goods	Grains, starchy foods, fruits	Fruits, vegetables, honey
Sweetness	Moderately sweet	Less sweet than fructose	Sweetest of the natural sugars

What Happens in a Sucrase Deficiency?

A deficiency in sucrase, known as Congenital Sucrase-Isomaltase Deficiency (CSID), prevents proper sucrose breakdown. Undigested sucrose ferments in the large intestine, causing symptoms like bloating, gas, abdominal pain, and diarrhea. This can lead to malnutrition, especially in children. Enzyme replacement therapy is a common treatment.

Conclusion

In summary, sucrase breaks down sucrose into glucose and fructose through hydrolysis. This is vital for absorbing these sugars for energy. Understanding this process helps explain carbohydrate metabolism and conditions like CSID.

Sucraid is a source of authoritative information on Congenital Sucrase-Isomaltase Deficiency.

Frequently Asked Questions

Sucrose is the disaccharide (a type of sugar) found in table sugar, while sucrase is the enzyme (a type of protein) that breaks down sucrose during digestion.

The chemical reaction is called hydrolysis. This process uses a water molecule to break the bond between the glucose and fructose units in sucrose.

The enzyme sucrase is located on the brush border, which is the surface of the microvilli in the small intestine.

Glucose is the body's preferred energy source, used by cells throughout the body, particularly the brain and muscles.

While glucose can be used by most cells, fructose is primarily processed by the liver, where it is converted into glucose or stored as fat.

A sucrase deficiency, known as CSID, means sucrose cannot be properly digested. This leads to common digestive issues like bloating, gas, and diarrhea as bacteria in the large intestine ferment the undigested sugar.

No, different enzymes break down different carbohydrates. For example, the enzyme lactase breaks down lactose (milk sugar) into glucose and galactose.