Characterization of Angiotensin-? Converting Enzyme Inhibiting Peptide from Venerupis philippinarum with Nano-Liquid Chromatography in Combination with Orbitrap Mass Spectrum Detection and Molecular Docking

The complexity and diversity of peptide mixture from protein hydrolysates make their characterization difficult. In this study, a method combining nano LC-MS/MS with molecular docking was applied to identifying and characterizing a peptide with angiotensin-? converting enzyme(ACE-I) inhibiting activity from Venerupis philippinarum hydrolysate. Firstly, ethanol supernatant of V. philippinarum hydrolysate was separated into active fractions with chromatographic methods such as ion-exchange chromatography and high performance liquid chromatography in combination. Then seven peptides from active fraction were identified according to the searching result of the MS/MS spectra against protein databases. Peptides were synthesized and subjected to ACE-Iinhibition assay. The peptide NTLTLIDTGIGMTK showed the highest potency with an IC_(50) of 5.75 μmol L^(-1). The molecular docking analysis showed that the ACE-I inhibiting peptide NTLTLIDTGIGMTK bond with residues Glu123, Glu403, Arg522, Glu376, Gln281 and Asn285 of ACE-I. Therefore, active peptides could be identified with the present method rather than the traditional purification and identification strategies. It may also be feasible to identify other food-derived peptides which target other enzymes and receptors with the method developed in this study.

Collagen derived species-specific peptides for distinguishing donkey-hide gelatin(Asini Corii Colla)

Objective:As an important food therapy product with traditional Chinese medicine(TCM) applications,donkey-hide gelatin(Asini Corii Colla,ACC) has been used for thousands of years.However,till now few effective strategy had been proposed to distinguish ACC from other animal hide gelatins,especially closely related horse-and mule-hide gelatins,which was an embarrassment of ACC quality control.Methods:Combined mass spectrometry and bioinformatic methods have been applied to identify and verify two ACC-specific peptides(Pep-1 and Pep-2) capable of distinguishing ACC from other closely related animal gelatins with high selectivity.Results:It confirmed that these two peptides could be not only used for distinguishing ACC from highly homologous horse-hide and mule-hide gelatins as well as other animal hide gelatins.Conclusion:The present study provides a simple method for species-specific peptides discovery,which can be used for assessing the quality of animal gelatin products,and ensure they are authenticable and traceable.

Heliangin acts as a covalent ligand of RPS2 that disrupts pre-rRNA metabolic processes in NPM1-mutated acute myeloid leukemia

Although NPM1 mutations are frequently found in acute myeloid leukemia patients,therapeutic strategies are scarce and unsuitable for those who cannot tolerate intensive chemotherapy.Here we demonstrated that heliangin,a natural sesquiterpene lactone,exerts favorable therapeutic responses in NPM1 mutant acute myeloid leukemia cells,with no apparent toxicity to normal hematogenous cells,by inhibiting their proliferation,inducing apoptosis,causing cell cycle arrest,and promoting differentiation.In-depth studies on its mode of action using quantitative thiol reactivity platform screening and subsequent molecular biology validation showed that the ribosomal protein S2(RPS2)is the main target of heliangin in treating NPM1 mutant AML.Upon covalent binding to the C222 site of RPS2,the electrophilic moieties of heliangin disrupt pre-rRNA metabolic processes,leading to nucleolar stress,which in turn regulates the ribosomal proteins-MDM2-p53 pathway and stabilizes p53.Clinical data shows that the pre-rRNA metabolic pathway is dysregulated in acute myeloid leukemia patients with the NPM1 mutation,leading to a poor prognosis.We found that RPS2 plays a critical role in regulating this pathway and may be a novel treatment target.Our findings suggest a novel treatment strategy and lead compound for acute myeloid leukemia patients,especially those with NPM1 mutations.