The human intestinal oligopeptide transporter (PEPT1) facilitates the absorption of dipeptides, tripeptides, and many peptidomimetic drugs. In this study, a large number of peptides were selected to investigate the structural features required for PEPT1 transport. Binding affinity was determined in a Gly-Sar uptake inhibition assay, whereas functional transport was ranked in a membrane depolarization assay. Although most of the peptides tested could bind to PEPT1, not all were substrates. As expected, single amino acids and tetrapeptides could not bind to or be transported by PEPT1. Dipeptide transport was influenced by charge, hydrophobicity, size, and side chain flexibility. The extent of transport was variable, and unexpectedly, some dipeptides were not substrates of PEPT1. These included dipeptides with two positive charges or extreme bulk in either position 1 or 2. Our results identify key features required for PEPT1 transport in contrast to most previously described pharmacophores, which are based on the inhibition of transport of a known substrate.
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http://dx.doi.org/10.1021/jm0511029 | DOI Listing |
J Pept Sci
March 2025
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark.
Fluorescent probes are widely used in cellular imaging and disease diagnosis. Acting as substitute carriers, fluorescent probes can also be used to help transport drugs within cells. In this study, commonly used fluorophores, TAMRA (5-carboxytetramethylrhodamine), PBA (1-pyrenebutyric acid), NBD (nitrobenzoxadiazole), OG (Oregon Green), and CF (5-carboxyfluorescein) were conjugated with the dipeptide β-Ala-Lys, the peptide moiety of the well-established peptide transporter substrate β-Ala-Lys(AMCA) (AMCA: 7-amino-4-methyl-coumarin-3-acetic acid) by modifying it with respect to side-chain length and functional end groups.
View Article and Find Full Text PDFStem Cell Res Ther
January 2025
Department of Medicine, Veterans Affairs Medical Center, Washington, DC, USA.
Introduction: Effects of Dapagliflozin (Dapa) and Dapagliflozin-Saxagliptin combination (Combo) was examined on peripheral blood derived CD34 + Hematopoetic Stem Cells (HSCs) as a cellular CVD biomarker. Both Dapa (a sodium-glucose co-transporter 2 or SGLT2, receptor inhibitor) and Saxagliptin (a Di-peptydl-peptidase-4 or DPP4 enzyme inhibitor) are commonly used type 2 diabetes mellitus or T2DM medications, however the benefit of using the combination has not been evaluated for cardio-renal risk assessment, in a real-life practice setting, compared to a placebo.
Hypothesis: We hypothesized that Dapa will improve the outcomes when compared to placebo and the Combo maybe even more beneficial.
Appl Microbiol Biotechnol
January 2025
School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-Ro, Jangan-GuGyeonggi-Do 16419, Suwon-Si, South Korea.
Process intensification and simplification in biopharmaceutical manufacturing have driven the exploration of advanced feeding strategies to improve culture performance and process consistency. Conventional media design strategies, however, are often constrained by the stability and solubility challenges of amino acids, particularly in large-scale applications. As a result, dipeptides have emerged as promising alternatives.
View Article and Find Full Text PDFCommun Biol
January 2025
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA.
Arginine-rich dipeptide repeat proteins (R-DPRs) are highly toxic proteins found in patients with C9orf72-linked amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). R-DPRs can cause toxicity by disrupting the natural phase behavior of RNA-binding proteins (RBPs). Mitigating this abnormal phase behavior is, therefore, crucial to reduce R-DPR-induced toxicity.
View Article and Find Full Text PDFNPJ Sci Food
December 2024
Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Kyushu University, Fukuoka, Japan.
In a series of studies on blood-brain barrier transportable peptides, a soybean dipeptide, Tyr-Pro, penetrated the mouse brain parenchyma after oral intake and improved short and long memory impairment in acute Alzheimer's model mice. Here, we aimed to clarify the anti-dementia effects of this peptide administered to SAMP8 mice prior to dementia onset. At the end of the 25-week protocol in 16-week-old SAMP8 mice, Tyr-Pro (10 mg/kg/day) significantly improved the reduced spatial learning ability compared with that in the control and amino acid (Tyr + Pro) groups as indicated by the results of Morris water maze tests conducted for five consecutive days.
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