Synthesis and Evaluation of Human Serum Albumin-Modified Exendin-4 Conjugate via Heterobifunctional Polyethylene Glycol Linkage with Protracted Hypoglycemic Efficacy

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• 作者：Insoo Kim ; Tae Hyung Kim ; Kyungwan Ma ; Eun Seong Lee ; Dongin Kim ; Kyung Taek Oh ; Don Haeng Lee ; Kang Choon Lee ; Yu Seok Youn
• 刊名：Bioconjugate Chemistry
• 出版年：2010
• 出版时间：August 18, 2010
• 年：2010
• 卷：21
• 期：8
• 页码：1513-1519
• 全文大小：315K
• 年卷期：v.21,no.8(August 18, 2010)
• ISSN：1520-4812

文摘

Albumin conjugation is considered to be one of the most effective means of protracting the short in vivo lifespans of peptides and proteins. Here, we present a new long-acting antidiabetic exendin-4 conjugate linked with human serum albumin (HSA) via polyethylene glycol (PEG). As a first step toward synthesizing this conjugate, three artificial sulfhydryl groups were introduced in HSA using 2-iminothiolane at pH 8.0. This thiolated HSA was further reacted with the monomer fraction of exendin-4 (6 equiv) conjugated with maleimide-PEG_5k-N- hydroxysuccinimide (MAL-PEG_5k-NHS) for 3 h. Because of the presence of PEG molecules, the resulting conjugate (HSA−PEG−Ex4) was found to have a greater apparent molecular weight and a larger particle size (ca. 195 kDa and 9.48 ± 0.74 nm) than those of HSA-exendin-4 without the PEG linker (HSA−Ex4, ca. 84.3 kDa and 7.77 ± 0.98 nm). Although the receptor binding affinity of HSA−PEG−Ex4 on RIN-m5F cells was significantly lower than that of Ex4, its antihyperglycemic efficacy was slightly higher than that of Ex-4 and HSA−Ex4 in type 2 diabetic db/db mice. Furthermore, HSA−PEG−Ex4 had greater circulating t_1/2 and AUC_inf values than HSA-Ex and native exendin-4 by 2.1- and 10.3-fold, respectively. Accordingly, its hypoglycemic duration was greatly increased to 31.0 h at a dose of 250 nmol/kg vs that of native Ex4 (7.0 h). Results show that the HSA−PEG−Ex4 conjugate produced has distinct advantages over HSA−Ex4 without PEG. We believe that this exendin-4 derivative, which has the merits of albumin conjugation and PEGylation, has considerable potential as a novel type 2 antidiabetic agent.