What is the lipase?
The term lipase stands for a group of enzymes that can break down special dietary fats, so-called triacylglycerides, into their constituent parts. They therefore play a decisive role in digestion. In the human body, lipase occurs in several sub-forms that are formed at different locations but have the same effect.
They can occur both inside and outside the cells. In general, however, the term lipase refers to the form of the enzyme that is produced by the cells of the pancreas. This enzyme is therefore also called pancreatic lipase.
Task and function
Pancreatic lipase is produced in special cells of the pancreas, which release the enzyme together with the remaining digestive secretions of the pancreas into the small intestine via a duct system. This is where the enzyme develops its effect: The task of pancreatic lipase is to break down special dietary fats into their constituent parts, which is what makes their digestion possible in the first place. Since only one other enzyme besides pancreatic lipase can break down these dietary fats, the production of the enzyme is essential for digestion in the small intestine.
Already at the end of the duodenum the pancreatic lipase has split a large part of the fats. The dietary fats that are split by the lipase are called triacylglycerides (TAGs). These consist of three fatty acid chains that are connected to each other via glycerol.
Due to the size of these triacylglycerides, they cannot simply pass through the mucous membrane in the intestine and be absorbed. The function of pancreatic lipase is essential for this. By splitting the ester bond between the fatty acid chains and the glycerol, the size of the individual products is significantly reduced.
Since all products are also electrically neutrally charged, they can pass through the intestinal mucosa much more easily. In the intestinal mucosa, the individual fatty acids are again bonded with glycerol to form a triacylglyceride. Furthermore, they are incorporated into special transport proteins that enable them to enter the bloodstream.
In order for the pancreatic lipase in the small intestine to function fully, a number of conditions must still be met. As a digestive enzyme, the lipase is not released in its active form to the duct system in the pancreas. Activation only takes place in the small intestine.
This is done by the digestive enzymes chymotrypsin and trypsin. In addition to a basic pH value and calcium, a coenzyme must also be present. This coenzyme is called colipase.
The colipase is also released as an inactive precursor and is converted into the active form by the enzyme trypsin. Besides the cleavage of triacylglycerides, pancreatic lipase also has the function of cleaving retinyl esters. After cleavage, the resulting retinol can be absorbed into the body.
As vitamin A, retinol assumes some important functions in the body, such as the visual process. Other forms of the lipase group are found in the human body, for example in fatty tissue. Here, triacylglycerides are also broken down into their components. Although this does not aid digestion, it is nevertheless important for other important processes such as the provision of energy reserves during long breaks between meals or during endurance sports.
