Chymotrypsinogen

Overview

Chymotrypsinogen structure

Chymotrypsinogen is a zymogen or inactive precursor of the digestive enzyme chymotrypsin. It is synthesized in the pancreas and secreted into the small intestine, where it is activated to form chymotrypsin. This activation is crucial for the proper digestion of proteins in the diet.

Structure

Chymotrypsinogen is a single polypeptide chain composed of 245 amino acids. It has a molecular weight of approximately 25,000 daltons. The structure of chymotrypsinogen includes several disulfide bonds that stabilize its conformation. Upon activation, these bonds help maintain the structure of the active enzyme, chymotrypsin.

Activation

Activation of chymotrypsinogen

The activation of chymotrypsinogen occurs in the small intestine. It is initiated by the enzyme trypsin, which cleaves specific peptide bonds in chymotrypsinogen to produce active chymotrypsin. This process involves the removal of two dipeptides, resulting in the formation of three chains that are held together by disulfide bonds.

Function

Chymotrypsin, the active form of chymotrypsinogen, is a serine protease that plays a key role in the digestion of proteins. It preferentially cleaves peptide bonds on the carboxyl side of aromatic amino acids such as tyrosine, tryptophan, and phenylalanine. This specificity is due to the structure of the enzyme's active site, which accommodates these amino acids.

Clinical Significance

Deficiencies or malfunctions in the production or activation of chymotrypsinogen can lead to digestive disorders. For instance, insufficient activation can result in protein malabsorption, leading to nutritional deficiencies. Understanding the mechanisms of chymotrypsinogen activation and function is important in the context of pancreatic diseases and conditions affecting the digestive system.

Related pages

• Chymotrypsin
• Trypsinogen
• Pancreas
• Protease