title: Site-specific PEGylated Exendin-4 modified with a high molecular weight trimeric PEG reduces steric hindrance and increases type 2 antidiabetic therapeutic effects.
abstract: The purpose of this study was to optimize an Exendin-4 (Ex4-Cys) site-specific PEGylation method with a high-molecular-weight trimeric PEG. Here, we describe the preparation of C-terminal specific PEGylated Ex4-Cys (C40-tPEG-Ex4-Cys), which was performed using cysteine and amine residue specific coupling reactions between Ex4-Cys and activated trimeric PEG. The C40-PEG-Ex4-Cys was obtained at high yields (~83%) and characterized by MALDI-TOF mass spectrometry. The receptor binding affinity of C40-PEG(5K)-Ex4-Cys was 3.5-fold higher than that of N-terminal PEGylated Ex4-Cys (N(ter)-PEG(5K)-Ex4-Cys), and receptor binding by the trimeric PEG (tPEG; 23, 50 kDa) adduct was much higher than that of branched PEG (20 kDa). Furthermore, C40-tPEG(50K)-Ex4-Cys was found to have greater blood circulating t(1/2) and AUC(inf) values than native Ex4-Cys by 7.53- and 45.61-fold, respectively. Accordingly, its hypoglycemic duration was much greater at 59.2 h than that of native Ex4-Cys at 7.3 h, with a dose of 25 nM/kg. The results of this study show that C-terminal specific PEGylation using trimeric PEG is effective when applied to Ex4-Cys and suggest that C40-tPEG(50K)-Ex4-Cys has considerable potential as a type 2 antidiabetic agent.
authors.affiliation: College of Pharmacy, SungKyunKwan University, 300 Chonchon-dong, Suwon City 440-746, Korea.
authors.forename: Tae Hyung
authors.initials: TH
authors.lastname: Kim
authors.forename: Hai Hua
authors.initials: HH
authors.lastname: Jiang
authors.forename: Sung Mook
authors.initials: SM
authors.lastname: Lim
authors.forename: Yu Seok
authors.initials: YS
authors.lastname: Youn
authors.forename: Ki Young
authors.initials: KY
authors.lastname: Choi
authors.forename: Seulki
authors.initials: S
authors.lastname: Lee
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Chen
authors.forename: Youngro
authors.initials: Y
authors.lastname: Byun
authors.forename: Kang Choon
authors.initials: KC
authors.lastname: Lee
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D000077270:Exenatide; D007004:Hypoglycemic Agents / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D008970:Molecular Weight; D010455:Peptides / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014688:Venoms / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000627:therapeutic use*
chemical_list: D007004:Hypoglycemic Agents; D010455:Peptides; D014688:Venoms; D011092:Polyethylene Glycols; D000077270:Exenatide