based on the residues in the active site pepsin belongs to the acid proteases family of proteases.
based on the residues in the active site pepsin belongs to the acid proteases family of proteases.
based on the residues in the active site what family of proteases does pepsin belong to?
acid proteases
pepsin may be inhibited by high ph (see "activity" and "stability", above) or by inhibitor compounds. pepstatin is a low molecular weight compound and potent inhibitor specific for acid proteases with a ki of about 10 m for pepsin. the statyl residue of pepstatin is thought to be responsible for pepstatin inhibition of pepsin; statine is a potential analog of the transition state for catalysis by pepsin and other acid proteases. pepstatin does not covalently bind pepsin and inhibition of pepsin by pepstatin is therefore reversible. 1-bis(diazoacetyl)-2-phenylethane reversibly inactivates pepsin at ph 5, a reaction which is accelerated by the presence of cu(ii).
pepsin
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