title: Amino group PEGylation of bovine lactoferrin by linear polyethylene glycol-p-nitrophenyl active esters.
abstract: PEGylation, the covalent attachment of polyethylene glycol (PEG) to pharmaceutical proteins, is regarded as an extremely useful procedure to generate protein drugs with intensified therapeutic properties. We examined the amino group modification of bovine lactoferrin (bLF) with linear PEG-p-nitrophenyl active esters. At pH 5.0, we specifically observed the formation of mono-PEGylated bLF in high yields. PEG-conjugation reactions advanced slowly and reached a steady state by 48 h in a buffer at pH 5.0. The hydrolysis half-lives of 5-kDa and 30-kDa PEG-p-nitrophenyl active esters at pH 5.0 were estimated to be approximately 117 and 136 h, respectively. The slow reaction and hydrolysis rates of PEG-p-nitrophenyl active esters may contribute to the formation of mono-PEGylated bLF that could not be obtained by PEGylation with linear N-hydroxysuccinimide (NHS) activated PEG.
authors.affiliation: School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo 192-0982, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Kato
authors.forename: Naomi
authors.initials: N
authors.lastname: Tamaki
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Saito
authors.forename: Tomohito
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sato
mesh_terms: D000818:Animals; D002417:Cattle; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D007781:Lactoferrin / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000378:metabolism*
chemical_list: D011092:Polyethylene Glycols; D007781:Lactoferrin