title: The tandem chain extension aldol reaction used for synthesis of ketomethylene tripeptidomimetics targeting hPEPT1.
abstract: The rationale for targeting the human di-/tripeptide transporter hPEPT1 for oral drug delivery has been well established by several drug and prodrug cases. The aim of this study was to synthesize novel ketomethylene modified tripeptidomimetics and to investigate their binding affinity for hPEPT1. Three related tripeptidomimetics of the structure H-Phe-ψ[COCH(2)]-Ser(Bz)-X(aa)-OH were synthesized applying the tandem chain extension aldol reaction, where amino acid derived β-keto imides were stereoselectively converted to α-substituted γ-keto imides. In addition, three corresponding tripeptides, composed of amide bonds, were synthesized for comparison of binding affinities. The six investigated compounds were all defined as high affinity ligands (K(i)-values <0.5 mM) for hPEPT1 by measuring the concentration dependent inhibition of apical [(14)C]Gly-Sar uptake in Caco-2 cells. Consequently, the ketomethylene replacement for the natural amide bond and α-side chain modifications appears to offer a promising strategy to modify tripeptidic structures while maintaining a high affinity for hPEPT1.
authors.affiliation: Protein Chemistry, Biogen Idec Hemophilia, Waltham, MA 02451, USA. karina.thorn@biogenidec.com
authors.forename: Karina
authors.initials: K
authors.lastname: Thorn
authors.forename: Carsten Uhd
authors.initials: CU
authors.lastname: Nielsen
authors.forename: Palle
authors.initials: P
authors.lastname: Jakobsen
authors.forename: Bente
authors.initials: B
authors.lastname: Steffansen
authors.forename: Charles K
authors.initials: CK
authors.lastname: Zercher
authors.forename: Mikael
authors.initials: M
authors.lastname: Begtrup
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D018938:Caco-2 Cells; D006801:Humans; D000074011:Peptide Transporter 1; D011485:Protein Binding; D013237:Stereoisomerism; D027981:Symporters / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000447:Aldehydes; D000074011:Peptide Transporter 1; C082186:SLC15A1 protein, human; D027981:Symporters; C116609:3-hydroxybutanal