Lactoferrin conjugated with 40-kDa branched poly(ethylene glycol) has an improved circulating half-life.
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)].
Nojima
Yasuhiro
Y
School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo, Japan.
Suzuki
Yosuke
Y
Yoshida
Kazuhiro
K
Abe
Fumiko
F
Shiga
Tuneo
T
Takeuchi
Takashi
T
Sugiyama
Akihiko
A
Shimizu
Hirohiko
H
Sato
Atsushi
A
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
D011092:Polyethylene Glycols; D007781:Lactoferrin