What is the Difference Between Alpha Amylase and Alpha Glucosidase

The main difference between alpha-amylase and alpha-glucosidase is that alpha-amylase breaks down dietary carbohydrates into simple monosaccharides whereas alpha-glucosidase further degrades monosaccharides into glucose that is absorbable.

Alpha-amylase and alpha-glucosidase are two types of digestive enzymes that involve in the digestion of dietary carbohydrates into glucose. Both enzymes work on (1→4)-α-linkages.

Key Areas Covered

1. What is Alpha Amylase
   • Definition, Characteristics, Importance
2. What is Alpha Glucosidase
   • Definition, Characteristics, Importance
3. Similarities Between Alpha Amylase and Alpha Glucosidase
   • Outline of Common Features
4. Difference Between Alpha Amylase and Alpha Glucosidase
   • Comparison with Key Differences

Key Terms

Alpha Amylase, Alpha Glucosidase

What is Alpha Amylase

Alpha-amylase is the digestive enzyme that digests carbohydrates such as starch into simple monosaccharides such as glucose. Usually, the hydrolysis of alpha bonds of large alpha-linked polysaccharides such as starch and glycogen yields dextrins and maltose. On the other hand, alpha-amylase is the major form of amylase that occurs in humans and mammals. Also, alpha-amylase occurs in the seeds that contain starch as the food reserve. In addition, alpha-amylase is secreted into the decaying organic matter by fungi.

Figure 1: Hydrolysis of 1-4 linkage by Alpha-Amylase

Apart from the mouth, alpha-amylase occurs more prominently in the pancreatic juice. Usually, salivary amylase digests large, insoluble starch in the food into soluble starches such as amylodextrin, erythrodextrin, and achrodextrin. However, these small starches further digest into maltose by the Alpha-amylase in the saliva. The salivary alpha-amylase acts on linear α(1,4) glycosidic linkages. Also, salivary alpha-amylase is inactivated by the gastric pH in the stomach. Pancreatic α-amylase randomly cleaves the α(1-4) glycosidic linkages of amylose to yield dextrin, maltose, or maltotriose.          

What is Alpha Glucosidase

Alpha-glucosidase is the enzyme that locates in the brush border of the small intestine. Also, the alpha-glucosidase acts on the α(1-4) glycosidic bonds that are terminal and non-reducing. However, Alpha-glucosidase releases a single α-glucose molecule. Therefore, alpha-glucosidase digests starch and disaccharides into glucose. In contrast, the enzyme can have either animal, plant, bacterial, or fungal origin. In plants, this enzyme occurs in the endocellular compartments of the germinated and non-germinated cereals. Also, alpha-glucosidase controls the composition of the plant polysaccharides in the stage of plant maturation.

Figure 2: Alpha-Glucosidase Action

Importantly, alpha-glucosidase associates with several disease conditions in humans. They are the glycogen storage disease type II, diabetes, azoospermia, and antiviral agents. In glycogen storage disease type II, the disorder is due to the deficiency of alpha-glucosidase enzyme. Also, the enzyme alpha-glucosidase is inhibited reversibly in the intestine by the alpha-glucosidase inhibitor, acarbose. Significantly, this inhibition reduces glucose absorption due to delayed carbohydrate digestion. Therefore, acarbose prevents the development of the symptoms of diabetes. On the other hand, the diagnosis of azoospermia is by measurement of α-glucosidase activity in seminal plasma. Apart from that, the inhibition of α-glucosidase can prevent fusion of HIV and secretion of HBV.

Similarities Between Alpha Amylase and Alpha Glucosidase

• Alpha-amylase and alpha-glucosidase are two types of digestive enzymes that occur in the carnivores’ digestive system.
• Both enzymes occur in the small intestine.
• Both enzymes work on (1→4)-α-linkages.

Difference Between Alpha Amylase and Alpha Glucosidase

Definition

Alpha-amylase refers to the enzyme that causes the degradation of starch molecules and hydrolyzes them into small-chain dextrins by acting upon the α-1,4 glycosidic bonds while alpha-glucosidase refers to a glucosidase located in the brush border of the small intestine that acts upon α bonds: hydrolysis of terminal, non-reducing-linked α-D-glucose residues with release of D-glucose.

Occurrence

Alpha-amylase occurs in the mouth and small intestine while alpha-glucosidase occurs in the brush border of the small intestine.

Activity

Alpha-amylase degrades carbohydrates into disaccharides while alpha-glucosidase digests disaccharides into glucose.

Conclusion

In brief, alpha-amylase and alpha-glucosidase are two types of digestive enzymes of carbohydrates. Also, they digest carbohydrates in the small intestine of the digestive tract.  Usually, alpha-amylase digests carbohydrates such as starch into glucose while alpha-glucosidase digests disaccharides, that is maltose into glucose. Therefore, the main difference between alpha-amylase and alpha-glucosidase is the type of digestion of carbohydrates.  

References:

1. “Alpha-Amylase.” Wikipedia, Wikimedia Foundation, 29 Sept. 2022.
2. “Alpha-Glucosidase.” Alpha-Glucosidase – an Overview | ScienceDirect Topics.

Image Courtesy:

1. “Amylase hydrolysisl 1-4” By Boumphreyfr – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Catalytic Reaction for a-glucosidase” By Ccfreeny – Own Work (CC BY-SA 3.0) via Commons Wikimedia