What is the Difference Between Alpha Beta and Gamma Amylase?

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Amylase enzymes are essential for breaking down the glycosidic bonds within starch molecules, transforming complex carbohydrates into simpler sugars. They are categorized into three main classes: alpha-, beta-, and gamma-amylases, each targeting distinct segments of the carbohydrate molecule.

  1. Alpha-amylase: This enzyme can hydrolyze alpha bonds of large polysaccharides, including starch and glycogen, yielding shorter chains of dextrin and maltose. It is found in humans, animals, plants, and microbes, and is produced by the salivary glands in humans and other mammals.
  2. Beta-amylase: Primarily found in microbes and plants, beta-amylase cleaves the alpha-1,4-glucan chain in units of maltose. It has an optimum pH of 4.0–5.0 and is present in higher plants such as barley, wheat, sweet potato, and soybean.
  3. Gamma-amylase: This enzyme is an exonuclease that cleaves alpha-1,4 and alpha-1,6 glycosidic bonds from the non-reducing end of starch molecules. It has an optimum pH of 3.0 and can be found in both animals and plants.

In summary, the main differences between alpha, beta, and gamma amylases are their origin, substrate specificity, and optimum pH. Alpha-amylase works on random locations along the starch chain, beta-amylase cleaves the alpha-1,4-glucan chain in units of maltose, and gamma-amylase cleaves from the non-reducing end of the polysaccharide by cleaving both alpha-1,4 and alpha-1,6 glycosidic bonds.

Comparative Table: Alpha Beta vs Gamma Amylase

Here is a table comparing the differences between alpha, beta, and gamma amylase:

Feature Alpha Amylase Beta Amylase Gamma Amylase
Definition Alpha amylase is an enzyme that hydrolyzes alpha bonds of large polysaccharides, including starch and glycogen, yielding shorter chains of dextrin and maltose. Beta amylase is a type of amylase enzyme that works by acting on specific bonds of the starch molecule. Gamma amylase works from the non-reducing end of the polysaccharide by cleaving both alpha-1,4 bonds.
Optimal pH Alpha amylase has an optimal working pH of around 3.0. Beta amylase has an optimum pH of 4.0–5.0. Gamma amylase also has an optimum pH of 3.0.
Enzyme Classification Alpha amylase belongs to glycosidic hydrolase families, including family 15 in fungi species, family 31 in humans, and family 97 in bacteria species. Beta amylases are present in yeasts, molds, bacteria, and plants. Gamma amylases are also known for their efficiency in cleaving certain types of glycosidic linkages.
Source Alpha amylase is found in humans and other mammals, as well as in seeds containing starch and is secreted by many types of fungi. Beta amylases are present in yeasts, molds, bacteria, and plants. Gamma amylase is also found in seeds containing starch and is secreted by some fungi.

In summary, alpha amylase works by hydrolyzing alpha bonds of large polysaccharides, while beta and gamma amylases act on different bonds of the starch molecule. Alpha and gamma amylases have an optimal pH of around 3.0, while beta amylase has an optimum pH of 4.0–5.0. Alpha amylase is primarily found in humans, mammals, seeds, and fungi, while beta and gamma amylases have a more diverse range of sources, including yeasts, molds, bacteria, and plants.