title: Lactoferrin conjugated with 40-kDa branched poly(ethylene glycol) has an improved circulating half-life.
abstract: OBJECTIVE
  We developed a lactoferrin conjugate by modifying bovine lactoferrin (bLF) with a 40-kDa branched poly(ethylene glycol) (PEG) molecule (designated 40 k-PEG-bLf), and we evaluated its in vitro activities and pharmacokinetic properties.
  
  
  METHODS
  We prepared 40k-PEG-bLf by amino conjugation with N-hydroxysuccinimide-activated PEG. This conjugate was purified by cation exchange chromatography and its in vitro biological activities, such as iron binding, anti-inflammatory effects, and resistance to proteolytic enzymes were investigated. In vivo pharmacokinetics analyses, were also performed to examine the rate of clearance from the plasma in rats.
  
  
  RESULTS
  The 40k-PEG-bLf conjugate was fully active in iron binding and exhibited 97.1 +/- 5.5% (mean +/- S.E., n = 6) of the original anti-inflammatory activity. The in vitro peptic susceptibility of 40 k-PEG-bLf revealed that the proteolytic half-life increased at least 6-fold that of unmodified LF. This PEGylated conjugate demonstrated a plasma half-life that was 8.7-fold longer than that of the unmodified bLF in rats.
  
  
  CONCLUSIONS
  The 40k-PEG-bLf exhibited improved in vitro bioactivity and stability and enhanced pharmacokinetic properties as compared to those of the unmodified bLF and the 20 k-PEG-bLf conjugate, which was recently developed by PEGylation of bLF with a 20-kDa branched PEG [Nojima Y. et al. Bioconjugate Chem. 19:2253-2259 (2008)].
authors: School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo, Japan.
authors: Yasuhiro
authors: Y
authors: Nojima
authors: Yosuke
authors: Y
authors: Suzuki
authors: Kazuhiro
authors: K
authors: Yoshida
authors: Fumiko
authors: F
authors: Abe
authors: Tuneo
authors: T
authors: Shiga
authors: Takashi
authors: T
authors: Takeuchi
authors: Akihiko
authors: A
authors: Sugiyama
authors: Hirohiko
authors: H
authors: Shimizu
authors: Atsushi
authors: A
authors: Sato
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D006207:Half-Life; D007781:Lactoferrin / Q000097:blood* / Q000737:chemistry; D008297:Male; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D011092:Polyethylene Glycols; D007781:Lactoferrin