Difference Between Lipase and Amylase

Key Difference – Lipase vs Amylase
 

The enzyme can be a catalytic protein substance that greatly increases the rate and efficiency of a chemical reaction without actively participating in the chemical reaction itself. Lipase and Amylase are two major digestive enzymes. A lipase is an enzyme that belongs to the subclass of the esterases that catalyzes the hydrolysis of fats. An amylase is an enzyme that catalyzes the hydrolysis of starch into sugars. This is the key difference between amylase and lipase. The purpose of this article is to highlight the differences between lipase and amylase enzymes.

What is Lipase?

A lipase is an enzyme that catalyzes the hydrolysis of lipids. It belongs to a subclass of the esterases. Lipases complete vital roles in the digestion, transport and processing of dietary lipids such as triglycerides, fats, oils in human digestive tract. As an example, pancreatic lipase can break down dietary triglyceride in the digestive system and convert triglyceride substrates into monoglycerides and two fatty acids. Humans also have several lipase enzymes, including hepatic lipase, endothelial lipase, and lipoprotein lipase.

What is Amylase?

An amylase is a major digestive tract enzyme that catalyzes the hydrolysis of starch into simple sugars. They are glycoside hydrolases and act on α-1, 4-glycosidic bonds. Amylase is present in human saliva, where it initiates the chemical process of digestion. When food is ingested into the mouth, food that contains great amounts of starch but slight sugar content such as rice and potatoes, may obtain a slightly sweet taste as the food is chewed. This is because amylase converts some of their starch into sugar. The human pancreas and salivary gland also secrete alpha-amylase to hydrolyze dietary starch into disaccharides and tri-or oligosaccharides that are converted by other enzymes to glucose to supply the body with energy. Plants and some bacteria also produce amylase. Amylase was the first enzyme to be discovered and isolated by Anselme Payen in 1833. There are different amylases proteins labeled by different Greek letters.

What is the difference between Amylase and Lipase?

Definition:

Lipase: Lipase is an enzyme that is involved in the hydrolysis of lipids.

Amylase: Amylase is an enzyme involved in the hydrolysis of starch molecules into sugars.

Type of Enzyme and Classification:

Lipase: A sub-class of hydrolases known as Esterases

Amylase: Hydrolases. It is further classified into three groups known as α-amylases, β-amylase, and γ-Amylase.

Bond Type:

Lipase: Lipase acts on the ester bond in a lipid.

Amylase: Amylase acts on the glycosidic bonds in a carbohydrate.

Substrate:

Lipase: Fatty acids esters such as triglycerides, fats, oils

Amylase: Starch molecules

End Product:

Lipase: Glycerol, Di-glycerides, Mono-glycerides, fatty acids like less complex forms of fats

Amylase: Oligosaccharides (Dextrose, maltodextrin) and disaccharides (Maltose)

Enzyme Secretion Organ in the Human Body:

Lipase: Salivary lipase and pancreatic lipase are secreted by the salivary gland pancreas respectively. Other examples are hepatic lipase, endothelial lipase, and lipoprotein lipase.

Amylase: Salivary gland secretes salivary amylase and pancreatic amylase is secreted by the pancreas.

Function:

Lipase: Lipid metabolism

Amylase: Carbohydrate metabolism

Mechanism of Action:

Lipase: Fats are not water-soluble but lipase dissolves in water. Therefore, lipase cannot directly break down the fat molecules.  First, fat, bile salts from the gall bladder must break up fats and emulsify them into water-soluble beads.

Amylase: Both amylase and starch are water soluble substances, so amylase enzymes secreted into the digestive tract mix easily with food particles (chyme) and easily digest dissolved carbohydrate in that food.

Related Health Issues:

Lipase: Lysosomal lipase deficiency can cause the Wolman disease as well as Cholesteryl Ester Storage Disease (CESD) which are autosomal recessive diseases. Both diseases are caused by a mutation in the gene encoding the enzyme.

Amylase: An increased level of amylase in the blood serum is an indicator that the person could be suffering from acute pancreatic inflammation, peptic ulcer, ovarian cyst or even mumps.

Uses:

Lipase: It is used in baking industry, Laundry detergents, Biocatalyst, Production of alternative sources of energy.

Amylase:

Flour additive: Amylases are used in bread making process and thereby break down complex starch in flour into simple sugars. Yeast then feeds on these simple sugars and converts it into the alcohol and CO₂ and this imparts flavor and causes the bread to rise.

Fermentation: Both alpha and beta amylases are vital in brewing beer and alcohol made from sugars derived from starch.

Amylase removes starch from starched clothes and, therefore, it is used as a detergent.

 

References

Maton, Anthea, Jean Hopkins, Charles William McLaughlin, Susan Johnson, MaryannaQuon Warner, David LaHart and Jill D. Wright (1993).Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1.

Svendsen, A. (2000). Lipase protein engineering.BiochimBiophysActa, 1543 (2): 223–228.

Guo, Z. and Xu, X. (2005).New opportunity for enzymatic modification of fats and oils with industrial potentials.Org BiomolChem, 3(14): 2615–9.

 

Image Courtesy:

1. Lipase PLRP2 [Public domain], via Wikimedia Commons

2. “Salivary alpha-amylase 1SMD” by Own work. – From PDB entry 1SMD.. [Public Domain] via Commons