1. A Shelf Stable Fmoc Hydrazine Resin for the Synthesis of Peptide Hydrazides
Michael J Bird, Philip E Dawson Pept Sci (Hoboken). 2022 Sep;114(5):e24268. doi: 10.1002/pep2.24268. Epub 2022 Apr 16.
C-terminal hydrazides are an important class of synthetic peptides with an ever expanding scope of applications, but their widespread application for chemical protein synthesis has been hampered due to the lack of stable resin linkers for synthesis of longer and more challenging peptide hydrazide fragments. We present a practical method for the regeneration, loading, and storage of trityl-chloride resins for the production of hydrazide containing peptides, leveraging 9-fluorenylmethyl carbazate. We show that these resins are extremely stable under several common resin storage conditions. The application of these resins to solid phase peptide synthesis (SPPS) is demonstrated through the synthesis of the 40-mer GLP-1R agonist peptide "P5". These studies support the broad utility of Fmoc-NHNH-Trt resins for SPPS of C-terminal hydrazide peptides.
2. A practical method for preparing fluorescent-labeled glycans with a 9-fluorenylmethyl derivative to simplify a fluorimetric HPLC-based analysis
Mitsuhiro Kinoshita, Ai Saito, Sachio Yamamoto, Shigeo Suzuki J Pharm Biomed Anal. 2020 Jul 15;186:113267. doi: 10.1016/j.jpba.2020.113267. Epub 2020 Mar 20.
Analysis of glycans in glycoproteins is often performed by liquid chromatography (LC) separation coupled with fluorescence detection and/or mass spectrometric detection. Enzymatically or chemically released glycans from glycoproteins are usually labeled by reductive amination with a fluorophore reagent. Although labeling techniques based on reductive amination have been well-established as sample preparation methods for fluorometric HPLC-based glycan analysis, they often include time-consuming and tedious purification steps. Here, we reported an alternative fluorescent labeling method based on the synthesis of hydrazone and its reduction using 9-fluorenylmethyl carbazate (Fmoc-hydrazine) as a fluorophore reagent. Using isomaltopentaose and N-glycans from human IgG, we optimized the Fmoc-labeling conditions and purification procedure of Fmoc-labeled N-glycans and applied the optimized method for the analysis of N-glycans released from four glycoproteins (bovine RNase B, human fibrinogen, human α1-acid glycoprotein, and bovine fetuin). The complete workflow for preparation of fluorescent-labeled N-glycans takes a total of 3.5 h and is simple to implement. The method presented here lowers the overall cost of a fluorescently labeled N-glycan and will be practically useful for the screening of disease-related glycans or routine analysis at an early stage of development of biopharmaceuticals.
3. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance analyses of end-functionalized saccharidic polymers: an example of a useful analytical technique combination
F D'Agosto, M T Charreyre, C Pichot, G Dessalces, F Delolme Rapid Commun Mass Spectrom. 2004;18(6):664-72. doi: 10.1002/rcm.1385.
The living cationic polymerization of a saccharidic monomer (1,2:3,4-di-O-isopropylidene-6-O-(2-vinyloxyethyl)-D-galactopyranose, GVE) gives rise to aldehyde end-capped polymers (PGVE--CHO) of low molar masses (<10 000 Da) and low molar mass distribution (<1.2). These polymers were derivatized by selective introduction of either hexamethylenediamine (PGVE-NH2) or 9-fluorenylmethyl carbazate (PGVE-Fmoc) end groups. The resulting polymers were fully characterized by complementary use of nuclear magnetic resonance (1H NMR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The expected structure according to the polymerization mechanism, the occurrence of side reactions and the success of the post-functionalization reactions were confirmed.
