Lipase enzymes are fat hydrolysing enzymes. They are secreted from various organs, e.g. pancreas, intestine, gastric juice, adipose tissues, lysosomes, blood, etc. They hydrolyse triglycerides and other dietary fats to fatty acid and glycerol. They are a subclass of esterase enzymes, splitting ester to acid and alcohol.
Lipase Enzyme Definition
“Lipase is an enzyme that catalyses the hydrolysis of triglycerides into fatty acids and glycerol.”
In most of the living organisms, lipase enzymes are essential for digestion and transportation of lipids.
Lipase Enzyme Function and Types
Lipases are essential for various biological processes. The main function of lipases is the breakdown and transport of dietary lipids. Various types of lipases are involved in diverse processes such as fat metabolism, transportation, cell signalling, inflammation, etc.
|Types of Lipase Enzyme||Secretion and Function|
|Lingual lipase||Present in saliva and catalyse initial triglyceride digestion.|
|Gastric lipase||Present in gastric juice, here fat digestion is limited to triglycerides with short-chain fatty acids.|
|Pancreatic Lipase||Present in pancreatic secretion, it is the most important lipolytic enzyme. It hydrolyses most of the dietary fats to fatty acids and glycerol. Bile salts accelerate the function of pancreatic lipase.|
|Lysosomal acid lipase||They are present intracellularly in lysosomes. They regulate intracellular lipid stores. They degrade lipoproteins, that come by endocytosis.|
|Lipoprotein lipase||Present on the surface of cells, lining blood capillaries in adipose tissues and muscle. It hydrolyses triglycerides in the blood that is carried by lipoproteins from different organs.
Chylomicrons carry triglycerides from the intestine and VLDL lipoproteins carry triglycerides from the liver to bloodstream.
|Phospholipase||It hydrolyses phospholipids and takes part in the cell signalling pathways.
Phospholipases help in recycling the cell membrane constituents.
There are different classes of phospholipases. Phospholipase A2 is present in pancreatic secretion in an inactive form, which gets activated by the action of trypsin enzyme.
Phospholipase in snake venom breaks down the cell membrane of the victim.
|Lecithin cholesterol acyltransferase (LCAT)||It is involved in cholesterol transport.|
How does Lipase work?
Digestion and absorption of Fat
Digestion of fat begins in the mouth by the action of lingual lipase present in the saliva. Most of the fat present in the diet is digested in the duodenum by the action of pancreatic lipase. Lipase enzyme is water-soluble, so it can act only on the surface of fat molecules. Emulsification by bile salt breaks down the bigger fat molecules to smaller droplets and greatly enhances the surface area of fat molecules to be acted on by pancreatic lipase. Triglycerides are then hydrolysed to diglycerides, monoglycerides, fatty acid and glycerol.
Also see: Protease Enzyme
The resultant fatty acids and glycerol are taken up by the intestinal wall. Triglycerides are re-synthesised there and get transported to adipose, muscle and other tissues. Lipase present in the bloodstream again acts on these triglycerides and the resultant fatty acids and glycerol are taken up by tissues.
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Frequently Asked Questions
What foods contain lipase enzymes?
Lipase enzymes are synthesised in our body naturally. They are also present in some foods, which can be supplemented in the diet to help in digestion of fats. E.g. avocados, kefir (a fermented milk beverage), kimchi (a Korean dish made up of fermented vegetables), etc.
What does a high lipase level mean?
Lipase is majorly synthesised by the pancreas and helps in the digestion of fats to free fatty acids and glycerol. A small amount of lipase in the blood is normal but the high level of lipase has clinical significance and it indicates an inflammation of the pancreas or a pancreatic disease such as pancreatitis.
What are the 4 main digestive enzymes?
The four main digestive enzymes are:
- Lipase – Secreted from pancreas, intestine, stomach, adipose tissues. The main function is the breakdown of fats or triglycerides into free fatty acids and glycerol.
- Amylase – Secreted in saliva and by the pancreas. It helps in the digestion of carbohydrates. It catalyses the hydrolysis of polysaccharides into disaccharides.
- Protease – Secreted by stomach and pancreas. It catalyses the breakdown of proteins to peptides and amino acids. E.g. pepsin, trypsin, chymotrypsin, etc.
- Nuclease – Present in the pancreatic juice. It acts on nucleic acids and converts it to nucleotides and nucleosides. E.g. deoxyribonuclease, ribonuclease, etc.
What is the function of lipase enzyme?
The main function of lipase enzyme is the hydrolysis of fats. It catalyses the breakdown of triglycerides into fatty acids and glycerol.
What organ makes lipase?
Lipase is the main fat-digesting enzyme. It is produced in the pancreas, stomach, mouth, intestine and adipose tissues.