Obestatin is a gastrointestinal system peptide. The quantification of this peptide is conventionally performed using immunological techniques. In this study, a selective and sensitive HPLC method coupled with fluorescence detection for the quantitation of obestatin in human plasma was developed and validated. The separation was obtained on a C18 (4.6 × 100 mm, 3.5-μm particles) column using a mobile phase composed of acetonitrile and water, both including 0.1% trifluoroacetic acid. The developed method was found linear in the concentration range of 20 to 1000 ng/mL, with a coefficient of determination of 0.9982. The precision results were less than 10% and the accuracy results were between 92% and 107%. The detection and the quantification limit values were obtained as 2.8 and 9.4 ng/mL, respectively. Analyte solutions were found stable for 24 hours at room temperature, three freeze–thaw cycles, and 2 weeks at –20°C. The developed method was successfully used for the quantification of obestatin in human plasma samples. In conclusion, the developed method is sensitive and specific for measuring the plasma concentrations of obestatin.
Designing the antimicrobial peptide with centrosymmetric and amphipathic characterizations for improving antimicrobial activity
Antibiotic-resistant bacterial infections are becoming a serious health issue and will cause 10 million deaths per year by 2050. As a result, the development of new antimicrobial agents is urgently needed. Antimicrobial peptides (AMPs) are found in the innate immune systems of various organisms to effectively fend off invading pathogens. In this study, we designed a series of antimicrobial peptides (THL-2-1 to THL-2-9) with centrosymmetric and amphipathic properties, through substituting different amino acids on the hydrophobic side and at the centrosymmetric position to improve their antimicrobial activity. The results showed that leucine as a residue on the hydrophobic side of the peptide could enhance its antimicrobial activity and that glutamic acid as a centrosymmetric residue could increase the salt resistance of the peptide. Thus, the THL-2-3 peptide (KRLLRELKRLL-NH2) showed the greatest antimicrobial activity (MIC90 of 16 μM) against Gram-negative bacteria and had the highest salt resistance and cell selectivity among all the designed peptides. In summary, the results of this study provide useful references for the design of AMPs to enhance antimicrobial activity.
Membrane targeting with palmitoylated lysine added to PP1‐disrupting peptide induces PP1‐independent signaling
Protein phosphatase 1 (PP1)-disrupting peptides (PDPs), which are specific PP1 activators, were combined with a palmitoylated lysine for membrane targeting. The resulting peptide (PDP-Mem) localizes to the cell membrane and in vitro activates PP1α. However, when targeting peptides to cellular membranes, undesired effects induced by the targeting sequence were observed and need to be considered for future designs.
Protein phosphatase-1 (PP1) is a ubiquitous enzyme involved in multiple processes inside cells. PP1-disrupting peptides (PDPs) are chemical tools that selectively bind to PP1 and release its activity. To restrict the activity of PDPs to a cellular compartment, we developed PDP-Mem, a cell membrane-targeting PDP. The membrane localization was achieved through the introduction of a palmitoylated lysine. PDP-Mem was shown to activate PP1α in vitro and to localize to the membrane of HeLa Kyoto and U2OS cells. However, in cells, the combination of the polybasic sequence for cell penetration and the membrane targeting palmitoylated lysine activates the MAPK signaling pathway and induces cytoplasmic calcium release independently of PP1 activation. Therefore, when targeting peptides to cellular membranes, undesired effects induced by the targeting sequence and lipid modification need to be considered.
Nos missions
Nos missions Le Groupe français des peptides et des protéines (GFPP) est une association (au sens de la loi de 1901) qui rassemble depuis plus de quarante ans environ 200 membres adhérents qui sont de facto les participants aux congrès bisannuels du GFPP. Elle est administrée par un bureau composé de membres élus lors de …
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L’article Nos missions est apparu en premier sur Groupe Français des Peptides et Protéines.
GFPP history_timeline
L’article GFPP history_timeline est apparu en premier sur Groupe Français des Peptides et Protéines.
What are peptides and proteins?
