Enhanced Peptide Stability Against Protease Digestion Induced by Intrinsic Factor Binding of a Vitamin B12 Conjugate of Exendin-4

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• 作者：Ron L. Bonaccorso ; Oleg G. Chepurny ; Christoph Becker-Pauly ; George G. Holz ; Robert P. Doyle
• 刊名：Molecular Pharmaceutics
• 出版年：2015
• 出版时间：September 8, 2015
• 年：2015
• 卷：12
• 期：9
• 页码：3502-3506
• 全文大小：298K
• ISSN：1543-8392

文摘

Peptide digestion from proteases is a significant limitation in peptide therapeutic development. It has been hypothesized that the dietary pathway of vitamin B₁₂ (B₁₂) may be exploited in this area, but an open question is whether B₁₂-peptide conjugates bound to the B₁₂ gastric uptake protein intrinsic factor (IF) can provide any stability against proteases. Herein, we describe a new conjugate of B₁₂ with the incretin peptide exendin 4 that demonstrates picomolar agonism of the glugacon-like peptide-1 receptor (GLP1-R). Stability studies reveal that Ex-4 is digested by pancreatic proteases trypsin and chymotrypsin and by the kidney endopeptidase meprin 尾. Prebinding the B₁₂ conjugate to IF, however, resulted in up to a 4-fold greater activity of the B₁₂-Ex-4 conjugate relative to Ex-4, when the IF-B₁₂-Ex-4 complex was exposed to 22 渭g/mL of trypsin, 2.3-fold greater activity when exposed to 1.25 渭g/mL of chymotrypsin, and there was no decrease in function at up to 5 渭g/mL of meprin 尾.