title: Inhibition of intraerythrocytic proteasome retards the generation of hemorphins.
abstract: Hemorphins are a set of hemoglobin-derived opioid peptides. The production mechanism of these structural overlap peptides remains unclear. Based on the sequences of hemorphins, it could be inferred that hemorphins are probably generated by cleavage of hemoglobin β chain at sites favored by the chymotrypsin-like protease. 20S proteasome possesses the chymotrypsin-like activity and still persists in mature erythrocytes. This study attempts to clarify whether the intraerythrocytic proteasome involves in the formation of hemorphins. Hemorphins containing hemorphin-7 and V-hemorphin-7 are isolated by immunoprecipitation from culture supernatant of human erythrocytes. Bortezomib inhibits the chymotrypsin-like activity of intraerythrocytic proteasome and prevents the yield of hemorphins in a dose-dependent manner. The present study suggests that intraerythrocytic proteasome contributes to the generation of hemorphins.
authors.affiliation: Initiative Project of Translational Medicine, Shandong Academy of Medical Sciences, Jinan 250062, China. songcz@sina.cn
authors.forename: Chang Zheng
authors.initials: CZ
authors.lastname: Song
authors.forename: Qing Wei
authors.initials: QW
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Chang Cheng
authors.initials: CC
authors.lastname: Song
mesh_terms: D001897:Boronic Acids / Q000494:pharmacology; D000069286:Bortezomib; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006454:Hemoglobins / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors; D011719:Pyrazines / Q000494:pharmacology
chemical_list: D001897:Boronic Acids; D006454:Hemoglobins; D010446:Peptide Fragments; D061988:Proteasome Inhibitors; D011719:Pyrazines; C085122:hemorphin 7; D000069286:Bortezomib; D046988:Proteasome Endopeptidase Complex