Question

What is the use of digestive enzymes?

Answer 1

Enzymes are proteins that act as biological catalysts or biocatalysts (molecules that accelerate biological reactions). Enzymes act on molecules called substrates and convert them to different molecules called products, passing through an intermediate stage called enzyme substrate complex.

Complete answer:
We know digestive enzymes are secreted by salivary glands and cells lining the stomach, small intestine and pancreas. These enzymes help in the breakdown of complex food particles into simpler forms so that they can be absorbed into the blood and transported to various parts of the body.
Main digestive enzymes are proteases, lipases, amylases and nucleases.
Let us discuss each of them briefly.
Proteases- also called peptidases; they help in breakdown of protein into amino acids. They are produced in the stomach and pancreas.
Lipases- They break down complex fat molecules into glycerol and fatty acids. These are produced in the pancreas.
Amylases- They are essential for the breakdown of complex carbohydrates into simple sugars. These are secreted by salivary glands, small intestine, and pancreas.
Nucleases- They act on the phosphodiester bonds of poly-nucleotides to form subsequent nucleotides and then nucleosides. These are secreted by the pancreas and small intestine.

Note:
Following table shows the various digestive enzymes, their source and substrate.

Enzyme	Source	Substrate
ProteasesPepsinTrypsinPeptidase	Stomach liningPancreasSmall intestine	ProteinsProteinsProteins
Lipases	Pancreas	Fats
AmylasesSalivary amylasePancreatic amylaseMaltaseLactase	Salivary glandsPancreasSmall intestineSmall intestine	Starch PolysaccharidesMaltoseLactose
NucleasesNucleaseNucleosidase	PancreasSmall intestine	Polynucleotide(DNA/ RNA)Nucleotide