pepsin is most active in the liver.
pepsin is most active in the liver.
where is pepsin most active in the body?
in the liver
pepsin is most active in acidic environments between 37 °c and 42 °c. accordingly, its primary site of synthesis and activity is in the stomach (ph 1.5 to 2). pepsin will digest up to 20% of ingested amide bonds by cleaving preferentially at the c-terminal side of aromatic amino acids such as phenylalanine, tryptophan, and tyrosine. pepsin exhibits preferential cleavage for hydrophobic, preferably aromatic, residues in p1 and p1' positions. increased susceptibility to hydrolysis occurs if there is a sulfur-containing amino acid close to the peptide bond, which has an aromatic amino acid. pepsin cleaves pheval, glnhis, gluala, alaleu, leutyr, tyrleu, glyphe, phe in the insulin b chain. pepsin exhibits maximal activity at ph 2.0 and is inactive at ph 6.5 and above, however pepsin is not fully denatured or irreversibly inactivated until ph 8.0. therefore, pepsin in solution of up to ph 8.0 can be reactivated upon re-acidification. the stability of pepsin at high ph has significant implications on disease attributed to laryngopharyngeal reflux. pepsin remains in the larynx following a gastric reflux event. at the mean ph of the laryngopharynx (ph = 6.8) pepsin would be inactive but could be reactivated upon subsequent acid reflux events resulting in damage to local tissues.
pepsin
pepsin may also cause mucosal damage during weakly acidic or non-acid gastric reflux. weak or non-acid reflux is correlated with reflux symptoms and mucosal injury. under non-acid conditions (neutral ph), pepsin is internalized by cells of the upper airways such as the larynx and hypopharynx by a process known as . the receptor by which pepsin is endocytosed is currently unknown. upon cellular uptake, pepsin is stored in intracellular vesicles of low ph at which its enzymatic activity would be restored. pepsin is retained within the cell for up to 24 hours. such exposure to pepsin at neutral ph and endocyctosis of pepsin causes changes in gene expression associated with inflammation, which underlies signs and symptoms of reflux, and tumor progression. this and other research implicates pepsin in carcinogenesis attributed to gastric reflux.
pepsin