digestive enzymes

Examples of digestive enzymes in the following topics:

• Pancreatic Juice

  • Pancreatic fluid contains digestive enzymes that help to further break down the carbohydrates, proteins, and lipids in the chyme.
  • The pancreas is a glandular organ in the digestive system and endocrine system of vertebrates.
  • It is both an endocrine gland that produces several important hormones—including insulin, glucagon, somatostatin, and pancreatic polypeptide—and a digestive organ that secretes pancreatic juice that has digestive enzymes that assist the absorption of nutrients and digestion in the small intestine.
  • These enzymes help to further break down the carbohydrates, proteins, and lipids in the chyme.
  • Because the pancreas is a sort of storage depot for digestive enzymes, injury to the pancreas is potentially fatal.

• Pancreas

  • The pancreas produces digestive enzymes and hormones, which are important in blood sugar regulation and other body functions.
  • It contains both exocrine cells that excrete digestive enzymes and endocrine cells that release hormones.
  • As a digestive organ, the pancreas secretes pancreatic juice containing digestive enzymes that assist the absorption of nutrients and the digestion in the small intestine.
  • These enzymes help to further break down the carbohydrates, proteins, and lipids in the chyme.

• Digestive Processes of the Small Intestine

  • The small intestine uses different enzymes and processes to digest proteins, lipids, and carbohydrates.
  • The small intestine is where most chemical digestion takes place.
  • Most of the digestive enzymes in the small intestine are secreted by the pancreas and enter the small intestine via the pancreatic duct.
  • Brush border enzymes take over from there.
  • Other brush border enzymes are maltase, sucrase, and lactase.

• Chemical Digestion of Carbohydrates, Proteins, Lipids, and Nucleic Acids

  • Chemical breakdown of macromolecules contained in food is completed by various enzymes produced in the digestive system.
  • Protein digestion occurs in the stomach and the duodenum through the action of three primary enzymes: pepsin, secreted by the stomach, and trypsin and chymotrypsin, secreted by the pancreas.
  • These enzymes break down food proteins into polypeptides, which are then broken down by various exopeptidases and dipeptidases into amino acids.
  • The digestive enzymes, however, are secreted mainly as their inactive precursors, the zymogens.
  • Sucrase is an enzyme that breaks down disaccharide sucrose, commonly known as table sugar, cane sugar, or beet sugar.

• Digestion and Absorption

  • Mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes.
  • In chemical digestion, enzymes break down food into the small molecules the body can use.
  • Digestive enzymes are enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption by the body.
  • Digestive enzymes are found in the digestive tracts of animals.
  • Digestion of carbohydrates is performed by several enzymes.

• Pancreas

  • As a digestive organ, the pancreas secretes pancreatic juice that contains digestive enzymes that assist the absorption of nutrients and digestion in the small intestine.
  • The exocrine function of the pancreas is essential for digestion as it produces many of the enzymes that break down the protein, carbohydrates, and fats in digestible foods.
  • The cells are filled with secretory granules containing the inactivated digestive enzymes, mainly trypsinogen, chymotrypsinogen, pancreatic lipase, and amylase, that are secreted into the lumen of the acini.
  • The pancreas synthesizes its enzymes in the inactive form, known as zymogens, to avoid digesting itself.
  • The enzymes are activated once they reach the small intestine.

• Hormones of the Digestive System

  • There are five main hormones that aid and regulate the digestive system in mammals.
  • There are five main hormones that aid in regulation of the digestive system in mammals.
  • Gastrin is in the stomach and stimulates the gastric glands to secrete pepsinogen (an inactive form of the enzyme pepsin) and hydrochloric acid.
  • Cholecystokinin (CCK) is in the duodenum and stimulates the release of digestive enzymes in the pancreas and stimulates the emptying of bile in the gall bladder.

• Vertebrate Digestive Systems

  • The enzymes present in saliva also begin to chemically break down food.
  • The gastric juices, which include enzymes in the stomach, act on the food particles and continue the process of digestion.
  • In the small intestine, enzymes produced by the liver, the small intestine, and the pancreas continue the process of digestion.
  • The digestive enzymes of these animals cannot break down cellulose, but microorganisms present in the digestive system can.
  • The cud then passes onto the fourth stomach, the abomasum, where it is digested by enzymes produced by the ruminant.

• Mechanisms of Chemical Digestion

  • Chemical digestion is the process of breakdown of large macronutrients into smaller molecules by enzyme-mediated hydrolysis.
  • The proteolytic enzymes are all secreted in an inactive form, to prevent auto-digestion, and are activated in the lumen of the gut: by HCl in the case of the stomach pepsinogen; by enteropeptidase and trypsin in the case of the pancreatic enzymes.
  • Final digestion takes place by small intestine enzymes embedded in the brush border of the small intestine.
  • The enzymes are divided into endo- and exo-peptidases.
  • Stomach pepsin digests about 20% of the proteins, the rest is digested by pancreatic and small intestine enzymes.

• Lysosomes

  • Lysosomes are organelles that digest macromolecules, repair cell membranes, and respond to foreign substances entering the cell.
  • If no food is provided, the lysosome's enzymes digest other organelles within the cell in order to obtain the necessary nutrients.
  • The lysosome's hydrolytic enzymes then destroy the pathogen .
  • The membrane is a crucial aspect of its structure because without it the enzymes within the lysosome that are used to breakdown foreign substances would leak out and digest the entire cell, causing it to die.
  • They are so common in animal cells because, when animal cells take in or absorb food, they need the enzymes found in lysosomes in order to digest and use the food for energy.