HUMAN ALPHA AMYLASES

 HUMAN ALPHA AMYLASES

Alpha-amylase is an enzyme that plays a crucial role in the breakdown of

complex carbohydrates into simpler sugars. It is found in various organisms,

including plants, animals, and microorganisms. The primary function of

alpha-amylase is to catalyze the hydrolysis of starch and glycogen into

maltose, glucose, and other oligosaccharides. This process is essential for the

digestion of carbohydrates in the human body.

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Structure of alpha amylase:

Almost all alpha-amylases of known amino acid sequence were reported to

have the same basic structure, a barrel of eight parallel stretches of extended

chain surrounded by eight helices. Strong similarities are found in those areas

of the proteins believed to bind an essential calcium ion and at that part of the

active site that catalyzes bond hydrolysis in the substrates. The active site, as a

whole, is formed mainly of amino acids situated on loops joining extended

chains to the adjacent helix. Variations in the length and amino acid sequence

of these loops, from one alpha-amylase to another, provide the differences in

binding the substrates believed to account for the known variations in action

pattern of alpha-amylases of different biological origins.

The active site of alpha-amylase contains a trio of acidic groups (coloured

white and red) that do most of the work. GLU-233, ASP-197, and ASP-300

work together to cleave the connection

between two sugars in a starch chain. This

structure contains a short chain of five sugar

units (coloured yellow and orange) bound in

the active site. The site of cleavage is shown

in blue. A calcium ion, shown as the large red

sphere in the background, is found nearby

where it stabilizes the structure of the

enzyme. A chloride ion, shown as a green sphere, is bound underneath the

active site in many amylases, where it may assist the reaction18.

Role of alpha-Amylases (1,4-α-d-glucan glucohydrolase)

α-Amylase catalyses the first step in the digestion of starch, a main source of

carbohydrate in the human diet. It catalyses the cleavage of α-1,4-glycosidic

bonds of starch and other related polysaccharides to generate oligosaccharides

of varying lengths with α-configuration and α-limit dextrins, which constitute

the branched oligosaccharides.

Industrial Applications:

 Food Industry: Alpha-amylase is used in the production of various

food products, including bread, biscuits, and other baked goods, to

improve texture and enhance dough handling properties.

 Brewing Industry: It is a critical enzyme in the brewing process,

breaking down starch in malted barley into fermentable sugars, which

yeast can then convert into alcohol.

 Textile Industry: Alpha-amylase is used to remove starch-based sizing

agents from fabrics, preventing damage during weaving and providing

a softer finish to the fabric.

 Paper Industry: It is used to modify starch-based coatings on paper and

improve the paper's printability and strength.

 Medical Applications: Alpha-amylase levels in the blood or urine are

sometimes measured to diagnose certain medical conditions, such as

pancreatitis or salivary gland disorders.

 Genetic Engineering: With advances in biotechnology, researchers

have been able to modify the alpha-amylase gene in microorganisms to

enhance its stability, efficiency, and adaptability for industrial

applications19.