Protein digestion in human body

Protein digestion is the process of breaking down the protein into its simpler forms amino acids which is absorbed by the body for various purposes.

1. Protein digestion Protein digestion
Anup Muni Bajracharya

2. Digestion Digestion•the process of breaking down food
(complex) into simpler forms.
•Simpler forms can be absorbed into the
body and used within the body.
•the process of breaking down food
(complex) into simpler forms.
•Simpler forms can be absorbed into the
body and used within the body. Fats fatty acids and glycerol.
Proteins amino acids.
Carbohydrates glucose.
Fats fatty acids and glycerol.
Proteins amino acids.
Carbohydrates glucose.Digestion begins in the
 mouth (saliva) 
Food is formed
into
 bolus 
 
esophagus 
 
stomach 
In the stomach  release of enzymes
break down the food further a thick
semiliquid
 chyme
 
duodenum 
In the small intestine the larger part of
digestion takes place with the secretions
of
 bile, pancreatic juice and intestinal juice.

The intestinal walls are lined with
 villi
 
the
absorption of nutrients
Digestion begins in the
 mouth (saliva) 
Food is formed
into
 bolus 
 
esophagus 
 
stomach 
In the stomach  release of enzymes
break down the food further a thick
semiliquid
 chyme
 
duodenum 
In the small intestine the larger part of
digestion takes place with the secretions
of
 bile, pancreatic juice and intestinal juice.

The intestinal walls are lined with
 villi
 
the
absorption of nutrients

3. Protein Digestion Protein DigestionA.B
A.B

4. Digestion of protein in human body
In the mouth Digestion of protein in human body
In the mouthProteins remain unchanged in the mouth as the saliva does not have
any protein digesting enzymes.
However there is the formation of ball-like mixture of food and
saliva that forms in the mouth during the process of chewing-Bolus
Proteins remain unchanged in the mouth as the saliva does not have
any protein digesting enzymes.
However there is the formation of ball-like mixture of food and
saliva that forms in the mouth during the process of chewing-Bolus
No digestion in mouthA.B
A.B

5. In the stomach In the stomach•The food undergoes both mechanical and
chemical digestion.
•During the periodic muscular contractions of
the stomach, the food is churned and is mixed
thoroughly with the gastric juice secreted by
the gastric glands.
•This juice contains mucous hydrochloric acid
and two proteases viz, pepsinogen and
prorennin.
•Hydrochloric acid does not digest the proteins
but it activates the inactive enzymes
pepsinogen and prorennin to pepsin and
rennin.
•Hydrochloric acid also helps in maintaining the
proper acidic pH for the action of the protein
digesting enzymes.
•The food undergoes both mechanical and
chemical digestion.
•During the periodic muscular contractions of
the stomach, the food is churned and is mixed
thoroughly with the gastric juice secreted by
the gastric glands.
•This juice contains mucous hydrochloric acid
and two proteases viz, pepsinogen and
prorennin.
•Hydrochloric acid does not digest the proteins
but it activates the inactive enzymes
pepsinogen and prorennin to pepsin and
rennin.
•Hydrochloric acid also helps in maintaining the
proper acidic pH for the action of the protein
digesting enzymes.A.B
A.B

6. •The enzyme pepsin hydrolyses the large molecules of proteins into peptones
and other polypeptides (partially digested protein).
•Pepsin also can digest collagen.
•The enzyme rennin hydrolyses the milk protein casein into paracasein.
•Paracasein in the presence of calcium gets converted into calcium
paracaseinate.
•Pepsin converts this also into peptones. •The enzyme pepsin hydrolyses the large molecules of proteins into peptones
and other polypeptides (partially digested protein).
•Pepsin also can digest collagen.
•The enzyme rennin hydrolyses the milk protein casein into paracasein.
•Paracasein in the presence of calcium gets converted into calcium
paracaseinate.
•Pepsin converts this also into peptones.In the stomach
In the stomach A.B
A.B

7. In the intestine In the intestine•The chyme or the
semidigested proteins are
acted upon by the pancreatic
juice
•Pancreatic juice consists of
three protein digesting
enzymes namely trypsin,
chymotrypsin and
carboxypeptidase.
•Initially enzymes are inactive
stage but they become
activated under the influence
of the intestinal juice.
•The chyme or the
semidigested proteins are
acted upon by the pancreatic
juice
•Pancreatic juice consists of
three protein digesting
enzymes namely trypsin,
chymotrypsin and
carboxypeptidase.
•Initially enzymes are inactive
stage but they become
activated under the influence
of the intestinal juice.

8. •The enzyme trypsin breaks basic proteins into peptides.
•Chymotrypsin splits proteins into polypeptides and it also hydrolyses milk proteins.
•The carboxypeptidases break the polypeptide chain into a number of dipeptides.
•The intestinal juice also contains two digestive proteases viz., amino peptidases and dipeptidases
besides a non digestive protease called enterokinase which activates the proteases in the
pancreatic juice.
•The amino peptidases break up polypeptide chains to dipeptides and free aminoacids. The
dipeptidases break up dipeptides into individual amino acids. •The enzyme trypsin breaks basic proteins into peptides.
•Chymotrypsin splits proteins into polypeptides and it also hydrolyses milk proteins.
•The carboxypeptidases break the polypeptide chain into a number of dipeptides.
•The intestinal juice also contains two digestive proteases viz., amino peptidases and dipeptidases
besides a non digestive protease called enterokinase which activates the proteases in the
pancreatic juice.
•The amino peptidases break up polypeptide chains to dipeptides and free aminoacids. The
dipeptidases break up dipeptides into individual amino acids. In the intestine
In the intestineA.B
A.B

9. Absorption Absorption•The amino acids are finally absorbed by the
villi present in the inner wall of the small
intestine.
•Amino acids
 are transported into the blood.
•The small peptides are transported into the
cells lining the small intestine where
intracellular
 peptidases  convert them into
amino acids that then enter the blood.
•Absorption is basically Na+-dependent
active process linked with the transport of
Na+.
•As the Na+ diffuses along the concentration
gradient, the amino acid also enters the
intestinal cell.
•Both Na+ and amino acids share a common
carrier and are transported together. The
energy is supplied indirectly by ATP.
•The amino acids are finally absorbed by the
villi present in the inner wall of the small
intestine.
•Amino acids
 are transported into the blood.
•The small peptides are transported into the
cells lining the small intestine where
intracellular
 peptidases  convert them into
amino acids that then enter the blood.
•Absorption is basically Na+-dependent
active process linked with the transport of
Na+.
•As the Na+ diffuses along the concentration
gradient, the amino acid also enters the
intestinal cell.
•Both Na+ and amino acids share a common
carrier and are transported together. The
energy is supplied indirectly by ATP.A.B
A.B

10. H+ dependent symport system for small peptides H+ dependent symport system for small peptidesA.B
A.B