What is the function of maltase in the human body?

November 25, 2025 •

2 min read

In humans, the enzyme maltase is synthesized by cells lining the intestinal wall, where it plays a critical role in nutrient absorption. The primary function of maltase is to catalyze the final step of carbohydrate digestion by breaking down the disaccharide maltose into absorbable glucose units.

Quick Summary

Maltase is an enzyme found on the small intestine's brush border that catalyzes the hydrolysis of maltose into two glucose molecules. This final breakdown is essential for the absorption of carbohydrates and subsequent energy production in the body.

Key Points

Specific Hydrolysis: The primary function of maltase is to catalyze the hydrolysis of the disaccharide maltose.
Glucose Production: The result of this hydrolysis is the creation of two individual, absorbable glucose molecules.
Small Intestine Location: Maltase is produced by and functions on the brush border of the small intestine's lining.
Energy Provision: By breaking maltose into glucose, maltase ensures the body has a usable source of energy from carbohydrates.
Two-Step Process: Maltase completes the carbohydrate digestion process that is initiated by the enzyme amylase in the mouth and pancreas.
Clinical Relevance: A deficiency in this enzyme can lead to significant digestive issues, including bloating, cramps, and diarrhea.

The Core Function of Maltase

Maltase is a glycoside hydrolase responsible for breaking down the disaccharide maltose into two molecules of glucose. This process occurs in the small intestine through hydrolysis, where a water molecule is used to cleave the $\alpha-(1\rightarrow4)$ glycosidic bond linking the two glucose units in maltose. The resulting glucose is then readily absorbed into the bloodstream, providing energy for the body.

Maltase's Role in Human Digestion

Maltase plays a crucial role in the multi-step digestion of carbohydrates, particularly starch. After enzymes like amylase break down starch into smaller maltose molecules in the mouth and small intestine, maltase, located on the brush border of the small intestine, acts on these maltose molecules. This final conversion to glucose is essential for absorption.

Additional Maltase Activities

Maltase is part of a family of enzymes called $\alpha$-glucosidases, with various forms like maltase-glucoamylase and sucrase-isomaltase contributing to carbohydrate digestion.

Factors Affecting Maltase Activity

Maltase activity is influenced by environmental conditions. It functions best in the slightly alkaline pH (7.0 to 8.5) of the small intestine and at body temperature (around 37°C). Extreme pH levels or temperatures can denature the enzyme and reduce its effectiveness.

Consequences of Maltase Deficiency

A deficiency in maltase can lead to digestive problems as undigested maltose reaches the large intestine and is fermented by bacteria, causing symptoms like bloating, cramps, gas, and diarrhea. Acid Maltase Deficiency (Pompe disease) is a distinct genetic disorder involving the accumulation of glycogen in cells due to a deficiency in acid $\alpha$-glucosidase.

Maltase vs. Amylase: A Comparison


Feature	Maltase	Amylase
Function	Breaks down maltose into glucose.	Breaks down starch (polysaccharides) into maltose.
Substrate	Maltose (a disaccharide).	Starch and glycogen (polysaccharides and oligosaccharides).
Product	Two molecules of glucose.	Maltose and other smaller oligosaccharides.
Location	Brush border of the small intestine.	Salivary glands (salivary amylase) and pancreas (pancreatic amylase).
Process	Catalyzes the final stage of carbohydrate digestion.	Initiates the first stage of carbohydrate digestion.

Industrial Applications

Maltase and related enzymes have applications in industries like brewing and baking, where they help convert starches into fermentable sugars. Research into $\alpha$-glucosidase inhibitors is also ongoing for potential diabetes treatments. For more on the physiological processes of digestion, refer to the National Library of Medicine on Digestion.

Conclusion: The Critical Role of Maltase

In summary, the function of maltase is essential for completing carbohydrate digestion. This enzyme, located in the small intestine, hydrolyzes maltose into glucose, a readily absorbable energy source. Without functional maltase, the body struggles to process dietary carbohydrates, leading to digestive issues and reduced energy uptake.

Frequently Asked Questions

The main function of maltase is to break down the sugar maltose into two molecules of glucose. This is the final step in digesting starches and other complex carbohydrates into a form the body can absorb for energy.

Maltase is produced by the enterocytes, which are the cells lining the small intestine. It is found on the surface of the microvilli, known as the brush border, where it acts on passing carbohydrates.

A deficiency in maltase means the body can't properly digest maltose. The undigested sugar then travels to the large intestine, where it is fermented by bacteria, causing symptoms like bloating, gas, abdominal cramps, and diarrhea.

Maltase works by a process called hydrolysis. It binds to a maltose molecule and uses a water molecule to cleave the $\alpha-(1\rightarrow4)$ glycosidic bond that holds the two glucose units together, releasing them as separate molecules.

Maltase is most active in the slightly alkaline conditions of the small intestine, with an optimal pH ranging from 7.0 to 8.5. Its activity is also optimal at human body temperature, approximately 37°C.

Amylase begins the process of carbohydrate digestion by breaking down large starch molecules into smaller maltose units. Maltase then takes over, converting the maltose into the final, absorbable glucose molecules.

Maltase is a specific type of $\alpha$-glucosidase. The term $\alpha$-glucosidase refers to a broader family of enzymes that break down glucose-containing carbohydrates. Maltase is primarily known for its action on the disaccharide maltose.

Yes, maltase is found in various other organisms, including plants, bacteria, and yeast. In these organisms, it plays a similar role in breaking down maltose.