PGC Human

Progastricsin-C is composed of 374 amino acid residues, which include a gastricsin moiety of 331 residues and an activation segment of 43 residues . The gene encoding human PGC is located on chromosome 6, while the human pepsinogen genetic locus is polymorphic and codes for at least three distinct polypeptide sequences on chromosome 11 . The crystal structure of human PGC reveals a bilobal structure with a large active-site cleft between the lobes, where two aspartate residues (Asp32 and Asp215) function as catalytic residues .

Progastricsin-C is secreted into the gastric lumen, where it is converted into its active form, pepsin C, under acidic conditions . This active enzyme is a major component of the gastric fluid and is responsible for the proteolytic digestion of dietary proteins . In addition to its digestive role, PGC is also present in seminal plasma, where it exhibits aspartyl proteinase-like activity and contributes to the production of pro-antimicrobial substances .

Progastricsin-C has been studied extensively for its potential role in various diseases, particularly cancer. The expression of PGC is significantly decreased in the progression from superficial gastritis to atrophic gastritis and eventually to gastric cancer . This makes PGC a valuable negative marker for gastric cancer. Additionally, ectopic expression of PGC has been observed in prostate, breast, ovarian, and endometrial cancers, where high levels of PGC expression are associated with better prognosis and longer survival .

Recombinant Progastricsin-C is produced using recombinant DNA technology, which involves inserting the gene encoding PGC into a suitable expression system, such as bacteria or yeast, to produce the protein in large quantities. This recombinant form is used in various research and clinical applications, including studies on its structure, function, and potential therapeutic uses.