Role of Digestive Enzymes in Digestion – Imaluop

Hi now we will study about the role of digestive enzymes in digestion. The food we take is not usable by our cells directly without breaking them down. During digestion specific types of digestive enzymes work on specific types of food molecules to break down them into simple form. Role of each digestive enzyme is important because biochemical reactions are enzyme specific. Now we will try to understand their role in digestion one by one.

Role of Digestive Enzymes in Digestion in Human Body:

In our digestive system different types of enzymes work on carbohydrates, protein and fat to break down them into simple monosaccharides, amino acids and fatty acids. They secreted in various parts of our digestive system.

Role of Salivary Gland Enzymes in Digestion:

Secretion of our salivary gland reaches into our oral cavity and there they perform their function. Salivary gland secretions have amylase which change the starch in our food into maltose. 30% of starch digestion occurs with the help of salivary amylase enzyme in our mouth cavity. 

Role of Gastric Gland Enzymes in Digestion:

In our stomach mucous membranes different types of gland present they secrete  all the gastric enzymes. Most important cells in our gastric mucosa is chief cells or peptic cells because they secrete proenzyme pepsinogen. Pepsinogen converts into active enzyme pepsin in the presence of hydrochloric acid secreted by the oxyntic cells present in our gastric mucosa layer.  Sometimes due to excess secretion of HCL from these oxyntic cells can cause acidity. Pepsin acts on protein and converts into proteases and peptones which need further treatment to become simple Amino Acids.

 Rennin is present in our gastric juice in infants stage which is required for milk protein digestion. Gastric glands secrete lipase enzymes which act on fat in our food into monoglycerides and diglycerides. 

Role of Small Intestine Enzymes in Digestion:

Our small intestine finalizes the breakdown process of almost all complex food molecules into simple form which can be absorbed and utilised by cells easily. Different types of secretion meet in our small intestine, from gallbladder bile juice, from pancreas pancreatic juice and from intestinal mucosa intestinal juice. 

1. Bile Juice: Bile juice is very important to digest fat because bile salts present in bile juice help to form emulsion. Without emulsion formation fat is difficult to digest because fat is not soluble in water due to its hydrophobic part. Lipase enzymes act on fat to break down it into simpler form but for activation of lipase bile juice is important. 
2. Pancreatic Juice: In our small intestine lumen pancreatic juice comes from pancreas which contains some proenzymes and some active enzymes. Inactive proenzymes present in our pancreatic juice are chymotrypsinogen, trypsinogen and procarboxypeptidase. Active enzymes present in our gastric juice are amylases, lipases and nucleases. 

• Chymotrypsinogen: It is an inactive form of chymotrypsin present in our pancreatic juice. Now how is chymotrypsinogen activation in our intestinal canal? The intestinal juice has the power to activate the proenzyme chymotrypsinogen into active form chymotrypsin. After activation chymotrypsin work on protein molecules and convert into dipeptides which requires further treatment to get most simple form amino acids. 

• Trypsinogen: It is also an inactive proenzyme present in our pancreatic juice. The proenzyme trypsinogen becomes active from trypsin with the help of enterokinase present in intestinal juice. After activation trypsin works on protein and converts into dipeptides in our small intestine. 

• Procarboxypeptidase: It is also an inactive proenzyme which becomes active form carboxypeptidases enzyme. Carboxypeptidases work on protein to break down it into simple form like other proteolytic enzymes.

• Lipagaes: Lipase enzymes present in our pancreatic juice work on fatty acids to convert into diglycerides.

• Nucleases: Pancreatic juice have nucleases which convert nucleic acid into simpler nucleotides and nucleosides.

• Amylases: The polysaccharides content in our food break down into disaccharides in our small intestine.

3.Intestinal Juice: Our Intestinal mucosa secrete following enzymes 

• Dipeptidases: This enzyme is responsible for converting dipeptides into simple amino acids monomers in our digestive tract.

• Disaccharidases: They convert all the disaccharides present in our digestive tract into monosaccharides.

• Lipases: This enzyme finishes the fat digestion in our digestive system converting monoglycerides and diglycerides into fatty acids.

• Nucleosidases: They are responsible for converting nucleotides into nucleosides in our small intestine.

• Lactases: They convert lactose in our digestive system into simple monosaccharide glucose molecules. 

Reference: Role of Digestive Enzymes in Digestion