N-terminal site-specific mono-PEGylation of epidermal growth factor.
OBJECTIVE
N-terminal site-specific mono-PEGylation of recombinant human epidermal growth factor (EGF) was accomplished using polyethyleneglycol (PEG) derivatives (Mw = 2000 and 5000) through a reactive terminal aldehyde group.


METHODS
The site-specific PEG conjugation was conducted ata slightly acidic pH condition (pH 5.5). The mono-PEGylation was targeted to an alpha-amine group at the N-terminal end of EGF to minimize reduction of biologic activity. Tryptic digestion mapping and MALDI-TOF MS techniques were applied to show the occurrence of mono-PEGylation at the N-terminus of EGF.


RESULTS
The site-specific mono-PEGylated EGF, when compared with native EGF, fully retained its in vitro biologic activities such a cell proliferation and intracellular signal transduction. This revealed that although a synthetic polymer of a PEG was covalently conjugated to EGF, the internalized complex of PEGylated EGF-receptor within cells did not hamper the intracellular signal transduction events. The PEGylated EGF also exhibited a prolonged circulation in blood stream in vivo and markedly enhanced physical stability whe incubated with tissue homogenate.


CONCLUSIONS
N-terminally mono-PEGylated EGF shows increased physical stability while retaining its biologic activity.
Department of Biologic Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
Haeshin
H
Lee
Il Ho
IH
Jang
Sung Ho
SH
Ryu
Tae Gwan
TG
Park
D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D019556:COS Cells; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002522:Chlorocebus aethiops; D004815:Epidermal Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D011092:Polyethylene Glycols / Q000378:metabolism*; D051381:Rats
D011092:Polyethylene Glycols; D004815:Epidermal Growth Factor