Question

Where does protein digestion starts?

Answer 1

after mechanically breaking down food in the mouth, protease enzymes which require acidic conditions (pepsin) attack the peptide links (-[C:O]-[NH]-) between certain amino acid pairs along the substrate protein chains causing the structure of the digested protein to break down through an enzymically assisted process of hydrolysis (-[C:O]-[NH]- + H2O = -[C:O.O-] + [NH2-]. In the duodenum the acid (HCl) of the stomach is neutralised and becomes alkaline so that proteolytic enzymes produced by the pancreas can further attack the oligopeptides produced by the gastric enzymes until individual amino acids are liberated which can be absorbed through the wall of the ileum.



Amino acids can be used by your body to form important cellular structures, such as enzymes, antibodies, hormones, muscle proteins, and collagen. Protein digestion begins with the action of an enzyme called pepsin. Pepsin is the active protein-digesting enzyme of the stomach.

So, we see that amino acids are the basic building blocks of protein. Amino acids can be used by your body to form important cellular structures, such as enzymes, antibodies, hormones, muscle proteins, and collagen. Protein digestion begins with the action of an enzyme called pepsin.

It’s digestion occurs in the stomach and duodenum in which 3 main enzymes, pepsin secreted by the stomach and trypsin and chymotrypsin secreted by the pancreas, break down food proteins into polypeptides that are then broken down by various exopeptidases and dipeptidases into amino acids.