fehérjelebontásban

Fehérjelebontás, also known as protein catabolism, is the metabolic process by which proteins are broken down into their constituent amino acids. This process is essential for several biological functions, including the recycling of amino acids for new protein synthesis, the generation of energy, and the removal of damaged or old proteins.

The breakdown of proteins begins in the stomach, where pepsin, an enzyme activated by the acidic environment, starts cleaving peptide bonds. Further digestion continues in the small intestine with the action of pancreatic enzymes like trypsin and chymotrypsin, which break down larger polypeptide chains into smaller peptides. Finally, peptidases on the brush border of the intestinal cells and intracellular peptidases further hydrolyze these peptides into individual amino acids.

Once amino acids are released, they can be absorbed into the bloodstream and transported to various tissues. In the cells, these amino acids can be reassembled into new proteins according to the body's needs. If the body has an excess of amino acids or requires energy, the amino group can be removed from an amino acid through deamination. The remaining carbon skeleton can then enter cellular respiration pathways to produce ATP, or it can be converted into glucose or fatty acids. The removed amino group is typically converted to ammonia, which is then detoxified in the liver and excreted as urea.

Fehérjelebontás is a tightly regulated process, influenced by hormonal signals and the nutritional status of the organism. It plays a crucial role in maintaining nitrogen balance and adapting to varying physiological demands.