What is the Difference Between Alpha and Beta Galactosidase

The key difference between alpha and beta galactosidase is that alpha galactosidase is an enzyme that is responsible for breaking down substrates that contain alpha galactosidic residues such as glycosphingolipids or glycoproteins, while beta-galactosidase is an enzyme that is responsible for breaking down the beta galactosides such as disaccharide lactose into its monosaccharide components, glucose and galactose. 

Galactosidases are enzymes that catalyze the hydrolysis of galactosides into monosaccharides. They are also called glycoside hydrolases. Galactosidases have various uses, including the production of prebiotics, removal of lactose and the biosynthesis of transgalactosylated products. Galactosidases can be classified into two types: alpha and beta-galactosidase.

CONTENTS

1. Overview and Key Difference
2. What is Alpha Galactosidase
3. What is Beta Galactosidase
4. Similarities – Alpha and Beta Galactosidase
5. Alpha vs Beta Galactosidase in Tabular Form
6. Summary – Alpha vs Beta Galactosidase

What is Alpha Galactosidase?

Alpha galactosidase is an enzyme that is responsible for breaking down substrates containing alpha galactosidic residues such as glycosphingolipids or glycoproteins. It is a glycoside hydrolase enzyme that hydrolyses the terminal alpha galactosyl moieties from glycolipids and glycoproteins. Furthermore, it cleaves glycoproteins, glycolipids, and polysaccharides. This enzyme specially catalyzes the removal of the terminal alpha galactose from oligosaccharides. Alpha galactosidase is encoded by the GLA gene.

Two recombinant forms of alpha-galactosidase are agalsidase alpha (INN) and agalsidase beta (INN). Beano is a supplement that assists in both flatulence, abdominal bloating, stomach pain, and a distended stomach. The primary ingredient in Beano is the mold-derived form of natural alpha galactosidase. This supplement is taken before eating food that usually causes these symptoms. Beano breaks down and digests complex carbohydrates such as those found in common vegetables, including broccoli, cauliflower, Brussels sprouts, and cabbage. This drug can also digest carbohydrates in legumes, including lentils, beans, nuts. However, this drug is not effective in preventing gas caused by difficulties in digesting lactose or fiber. Moreover, the defects in human alpha galactosidase result in Fabry disease. This disease is a rare lysosomal storage disorder and sphingolipidosis. This condition is a result of the failure to catabolize alpha D galactosyl glycolipid moieties.

What is Beta Galactosidase?

Beta galactosidase is an enzyme that is responsible for breaking down the beta galactosides such as disaccharide lactose into its monosaccharide components – glucose and galactose.  It is also a glycoside hydrolase enzyme that catalyzes the hydrolysis of beta galactosides into monosaccharides via the breaking of a glycosidic bond. Beta galactosides are carbohydrates containing galactose where the glycosidic bond lies above the galactose molecule. Ganglioside GM1, lactosylceramides, lactose, etc., are substrates for different beta galactosidases.

Beta galactosidase is encoded by the GLB1 gene in humans. In E.coli lacZ gene is the structural gene for beta galactosidase. The deficiency of beta galactosidase leads to two metabolic storage diseases: GM1 gangliosidosis (GM1) and Morquio B disease. These are inherited autosomal diseases. Moreover, this enzyme is commonly used in genetic and molecular biology as a reporter marker to monitor gene expression (blue-white screening).

What are the Similarities Between Alpha and Beta Galactosidase?

• Alpha and beta galactosidase are two types of galactosidases.
• They are glycoside hydrolases.
• They are proteins with enzymatic properties.
• Both are made up of amino acids.
• Both enzymes catalyze the hydrolysis of galactosides into monosaccharides.

What is the Difference Between Alpha and Beta Galactosidase?

Alpha galactosidase is an enzyme that is responsible for breaking down substrates that contain alpha galactosidic residues, while beta galactosidase is an enzyme that is responsible for breaking down the beta galactosides.  So, this is the key difference between alpha and beta galactosidase. Furthermore, alpha galactosidase is encoded by the GLA gene in humans while beta galactosidase is encoded by the GLB1 gene in humans.

The following infographic lists more differences between alpha and beta galactosidase in tabular form for side by side comparison.

Summary – Alpha vs Beta Galactosidase

Galactosidases are glycoside hydrolases that catalyze the hydrolysis of galactosides into monosaccharides. Alpha and beta galactosidase are two types of galactosidases. Alpha galactosidase breaks down substrates that contain alpha galactosidic residues while beta galactosidase breaks down beta galactosides such as disaccharide lactose into its monosaccharide components. Thus, this is the summary of the difference between alpha and beta galactosidase.

Reference:

1. “Alpha-Galactosidase.” An Overview | ScienceDirect Topics.
2. “Beta-Galactosidase.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “3a5v” By Deposition authors: Fujimoto, Z., Kaneko, S., Kobayashi, H.;visualization author: User:Astrojan – RCSB (CC BY-SA 4.0) via Commons Wikimedia
2. “Beta-galactosidase” By Jonathan A Jones at the English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia