Oligo(Glu70‐co‐Leu30), a peptide synthesized by protease catalysis, is functionalized at the N‐terminus with a 4‐pentenoyl unit and grafted to polyLSL[6′Ac,6″Ac], a glycopolymer prepared by ring‐opening metathesis polymerization of lactonic sophorolipid diacetate. First, polyLSL[6'Ac,6”Ac] fiber mats are fabricated by electrospinning. Oxidation of the fiber mats and subsequent reaction with cysteamine lead to thiol‐functionalized fiber mats with no significant morphology changes. Grafting of the alkene‐modified oligopeptide to thiol‐functionalized polyLSL[6′Ac,6″Ac] fiber mats is achieved via “thiol‐ene” click reaction. X‐ray photoelectron spectroscopy analysis to characterize peptide grafting reveals that about 50 mol% of polyLSL[6′Ac,6′′Ac] repeat units at fiber surfaces are decorated with a peptide moiety, out of which about 1/3 of the oligo(Glu70‐co‐Leu30) units are physically adsorbed to polyLSL[6′Ac,6′′Ac]. The results of this work pave the way to precise engineering of polyLSL fiber mats that can be decorated with a potentially wide range of molecules that tailor surface chemistry and biological properties.
A series of N-acetyl-L-glutamic acid oligopeptide benzyl esters with exact residue numbers 4, 6, and 12 has been synthesized by a stepwise procedure.
For these oligopeptide–dioxane binary systems, the behavior of the liquid-crystalline phases has been examined␣by the use
of 2H NMR, and the results indicate that highly ordered aggregates formed by these oligopeptides in dioxane are in an alignment
similar to that in a nematic mesophase.
Received: 27 February 2001 Accepted: 8 May 2001 相似文献
The aim of this study was to isolate and identify antioxidative peptide from goose liver hydrolysate (GLHP) for ameliorating oxidative stress damage by alcohol in HHL-5 hepatocytes. In this research, the target antioxidative peptides in GLHP were separated, purified, and identified via a tangential flow ultrafiltration system combined with size exclusion chromatography (SEC), ion exchange chromatography (IEC), reversed-phase liquid chromatography (RP-LC), and LC-MS/MS. The results suggested that the amino acid sequence of the target antioxidative peptide for ameliorating alcohol-mediated oxidative stress damage in HHL-5 hepatocytes was Leu-Pro-Leu-Pro-Phe-Pro (LPLPFP), which had a molecular weight of 683.41 Da, and was derived from NADH-ubiquinone oxidoreductase chain 1 in goose liver. In addition, LPLPFP was confirmed to have a satisfactory stability and maintained high hepatic protective activity in a simulated gastrointestinal digestion. Moreover, the mechanism of LPLPFP prevented against oxidative stress damage in HHL-5 hepatocytes was attributed to inhibiting the production of reactive oxide species (ROS) by upregulating genes expression in the Ahr-NQO1 signal pathway. In conclusion, these results indicated that dietary GLHP supplementation could ameliorate alcohol-mediated oxidative stress damage and provide an affordable dietary intervention strategy to prevent alcohol-mediated hepatocyte damage. 相似文献
Radical‐mediated dissociations of peptide radical cations have intriguing unimolecular gas phase chemistry, with cleavages of almost every bond of the peptide backbone and amino acid side chains in a competitive and apparently “stochastic” manner. Challenges of unraveling mechanistic details are related to complex tautomerizations prior to dissociations. Recent conjunctions of experimental and theoretical investigations have revealed the existence of non‐interconvertible isobaric tautomers with a variety of radical‐site‐specific initial structures, generated from dissociative electron transfer of ternary metal‐ligand‐peptide complexes. Their reactivity is influenced by the tautomerization barriers, perturbing the nature, location, or number of radical and charge site(s), which also determine the energetics and dynamics of the subsequent radical‐mediated dissociatons. The competitive radical‐ and charge‐induced dissociations are extremely dependent on charge density. Charge sequesting can reduce the charge densities on the peptide backbone and hence enhance the flexibility of structural rearrangement. Analysing the structures of precursors, intermediates and products has led to the discovery of many novel radical migration prior to peptide backbone and/or side chain fragmentations. Upon these successes, scientists will be able to build peptide cationic analogues/tautomers having a variety of well‐defined radical sites. 相似文献
The concentration dependent transformation of an oligopeptide nanostructure from nanovesicles to nanotubes at neutral pH is presented. The oligopeptide Acp‐Tyr‐Glu (Acp: 6‐aminohexanoic acid) forms nanovesicles at a concentration of 6.9 mg mL?1. At a concentration of 2.3 mg mL?1 these vesicular structures completely disappear and nanotubular structures are observed. We have also successfully optimized an intermediate concentration (3.4 mg mL?1) where an ordered array of fused vesicular structures are formed, which actually leads to the transition from nanovesicles to nanotubes. These vesicular structures are very much sensitive toward metal ions and pH. Biocompatible calcium ions and high pH (10.7) can trigger the rupturing of these nanovesicles. One important property of these nanovesicular structures is the encapsulation of a potent anticancer drug doxorubicin, which can also be released in the presence of calcium ions promising a future use of these nanovesicles as vehicles for carrying biologically important molecules. 相似文献