Kui Lu

Immobilization of DNA on a glassy carbon electrode based on Langmuir–Blodgett technique: application to the detection of epinephrine

A double-stranded (ds) DNA-octadecylamine Langmuir–Blodgett film was attached to the surface of glassy carbon electrode (GCE) to create a novel voltammetric sensor (DNA-LB/GCE) for epinephrine (EP). Atomic force microscopy and electrochemical impedance spectroscopy were employed to study the characteristic of the DNA-LB film. The electrochemical behavior of EP at the modified electrode was investigated in pH 6.0 phosphate buffer solutions by cyclic voltammetry and amperometric methods. Compared with bare GCE, the DNA-LB/GCE sensor demonstrated an electrocatalytic effect on the oxidation of EP. In addition, the sensor shows excellent selectivity for EP detection, being free of interference from excess ascorbic acid and uric acid, and the method was also applied successfully to detect EP in the human urine samples.

Syntheses of valpromide dipeptide derivatives and interactions of derivatives with ctDNA

Abstract Two types of valproamide dipeptides, i.e., valproic acid (VPA)-Tyr-Tyr and VPA-His-His, were synthesized via Fmoc solid-phase peptide synthesis, purified via reversed-phase HPLC, and characterized via 1H, 13C NMR and ESI–MS to promote the interaction of valproic acid derivative with biological molecular. The interactions of VPA-Tyr-Tyr and VPA-His-His with DNA were investigated via UV–Vis absorption spectroscopy, fluorescence spectroscopy, and gel electrophoresis. The results showed that both VPA-Tyr-Tyr and VPA-His-His interacted with ctDNA through the groove binding mode and exhibited higher affinity for ctDNA compared with free VPA. Therefore, the valpromide derivatives modified by dipeptides have significant practical value in future studies.

Substrates of the human oligopeptide transporter hPEPT2.

Oligopeptide transporters serve important functions in nutrition and pharmacology. In particular, these transporters help maintain the homeostasis of peptides. The peptide-transporter PEPT2 is a high-affinity and low-capacity type oligopeptide transporter from the proton-coupled oligopeptide transporter family. PEPT2 has recently received attention because of its potential application in targeted drug delivery. PEPT2 is widely distributed in kidney, central nervous system, and lung of organisms. In general, all dipeptides, tripeptides, and peptide-like drugs such as β-lactam antibiotics and angiotensin-converting enzyme inhibitors could be mediated and transported as a substrate of PEPT2. The design of many extant drugs and prodrugs is based on the substrate structure of PEPT2 to accelerate absorption via peptide transporters. Thus, this paper summarizes the substrate features of PEPT2 to promote the rational design of drugs and prodrugs that target peptide transporters.

Solid Phase Syntheses of Ferulic Acid Derivatives Acetyl Feruloyl Tyrosine and Acetyl Feruloyl Valyl Tyrosine

Ferulic acid was used as a common drug for cardia-cerebrovascular disease and leukopenia, but the application of ferulic acid was inhibited by the poor absorption and stability. The improvement of these defects can be realized by modifying ferulic acid by amino acids, because the amido bond can increase the bioavailability and therapeutic effect of some drugs based on the peptide transporter system of mammalian which can transport the peptidyl drugs. The peptidyl derivatives of ferulic acid, namely acetyl feruloyl tyrosine and acetyl feruloyl valyl tyrosine, were synthesized using Fmoc solid-phase synthesis method. The synthesized ferulic acid amide derivatives were purified by RP-HPLC, and characterized by IR, 1 HNMR and ESI-MS. The results indicated that Fmoc solid phase synthesis was a convenient method for the amide bond modification of ferulic acid and the further property research on ferulic acid derivatives.

Design and synthesis of BRC analogous peptides and their interactions with a key p53 peptide

Mutations in breast cancer susceptibility gene 2 (BRCA2) can lead to chromosomal instability and result in breast cancer, which is strongly associated with p53 mutations. Here, based on the crystal structure of BRC4 and p53, the spatial structure of BRC2 and p53 (171–192) was simulated, providing structural basis for the site‐specific mutation of BRC2. The BRC analogous peptides and p53 (171–192) were synthesized, and the interaction between the mutant peptide and p53 (171–192) was studied using circular diachronic spectroscopy and fluorescence spectroscopy. The results show that the mutations of amino acid residues constituting the BRC2 α‐helix significantly affect the structure and interaction of BRC analogs and p53 (171–192), which provides support for understanding the structure of the BRC repeat motifs and its interaction pattern with p53.

Concise Synthesis of Triazole-Linked 5′-Peptide-Oligonucleotide Conjugates by Click Chemistry

A concise synthesis of oligonucleotide 5′-peptide-conjugates via copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition in aqueous solution is described. Synthesis of reagents was accomplished by on-column derivatization of corresponding peptides and oligonucleotides. This method is well suited for the preparation of peptide–oligonucleotide conjugates containing 1,2,3-triazole linkage between the 5′-position of an oligonucleotide and the N-terminus of a peptide.