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Pepsin 中文

Which Enzyme Breaks Down Proteins into Peptides?

The primary enzyme responsible for initiating protein digestion by breaking down large protein molecules into smaller peptides is pepsin.Pepsin is an enzyme produced in the stomach that attacks ... Found in the gastric juices of the stomach, pepsin is a crucial protease that operates in the acidic environment of the stomach, making it the first major player in the enzymatic breakdown of dietary proteins. It effectively cleaves proteins into shorter chains of amino acids, known as polypeptides and peptides, which are then prepared for further digestion in the small intestine.

While pepsin is the principal enzyme in the stomach, the broader category of enzymes that break down proteins is known as proteases. Proteases are a diverse group of enzymes that catalyze proteolysis, the hydrolysis of peptide bonds within proteins. Pepsin is a specific type of protease, an endopeptidase, meaning it cleaves peptide bonds within the protein chain rather than at the ends.

Following pepsin's action in the stomach, the partially digested proteins move to the small intestine. Here, other powerful proteases, such as trypsin and chymotrypsin (produced by the pancreas), and carboxypeptidase (released by the cells lining the small intestine), continue the breakdown process. These enzymes further break down the peptides into even smaller peptides and, eventually, into individual amino acids, which are small enough to be absorbed into the bloodstream. Enzymes called peptidases are also involved in this final stage, breaking down remaining peptides into amino acids.

Therefore, while pepsin is the key enzyme that *begins* the process of breaking down proteins into peptides in the stomach, a coordinated effort involving various proteases and peptidases throughout the digestive system is essential for complete protein digestion and absorption.Pepsin is a potentenzyme(endopeptidase) thatbreaks down proteins intosmallerpeptidesaidinginthe digestion ofproteins.