What happens during protein digestion at the molecular level?

Protein digestion at the molecular level involves the stepwise breakdown of complex protein structures into absorbable amino acids through enzymatic action.

The process begins in the stomach, where hydrochloric acid denatures proteins, unfolding their complex three-dimensional structure. This exposes peptide bonds, making them accessible to enzymes. The enzyme pepsin then breaks proteins into smaller polypeptides.

In the small intestine, pancreatic enzymes such as trypsin, chymotrypsin, and carboxypeptidase further hydrolyze these polypeptides into shorter peptide chains and individual amino acids.

At the brush border of the intestinal lining, additional enzymes like peptidases complete the digestion by converting remaining peptides into free amino acids.

These amino acids are then absorbed through the intestinal epithelium into the bloodstream via active transport and facilitated diffusion. Once in circulation, they are transported to cells for protein synthesis, repair, and metabolic functions.

Overall, protein digestion is a highly regulated enzymatic process that converts large, complex molecules into simple units that the body can absorb and utilize efficiently.