3303-31-9Relevant articles and documents
First Steps for the Direct Purification of l -Leu- l -Leu Dipeptide through Co-Crystallization
Lucaioli, Paolo,Nauha, Elisa,Singh, Ishwar,Blagden, Nicholas
, p. 1062 - 1069 (2018)
Trifluoroacetate salt contamination of peptides represents a challenging issue related to solid phase peptide synthesis and purification because it affects the chemical and biological properties of peptides. Purification of such materials is typically performed through a two-step post-synthetic procedure based on chromatography followed by ion exchange. For the first time, co-crystallization is presented in this study as a possible alternative and advantageous single-step method for the obtaining of TFA-free crystals of a dipeptide. A trifluoroacetate-contaminated l-Leu-l-Leu dipeptide has been used for co-crystallization experiments along with different solid coformers. New multicomponent crystals containing only the title compound and the second co-crystal formers are described in this work. Such results represent a novelty in the field of peptide chemistry and a valid proof for the use of crystal engineering-based method for a combined purification and crystallization strategy.
A PROCESS FOR PREPARATION OF A PEPTIDE
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Page/Page column 18-19, (2018/07/29)
The present invention relates to a novel process for preparation of peptides having amino acid chain length in the range of 2-40 comprises the steps: i) attaching an end-blocked amino acid with an ionic liquid based solid support in presence of an ionic solvent to obtain an end-terminal blocked amino acid attached ionic liquid; ii) removing end-terminal blocking agent from the end-terminal blocked amino acid attached ionic liquid of step i) followed by work up to obtain an amino acid attached ionic liquid; iii) repeating steps i) through ii) one or more times to obtain a polypeptide attached ionic liquid; and iv) detaching the polypeptide from the polypeptide attached ionic liquid of step iii) to obtain the polypeptide. Said process does not use any auxiliary reagents like dehydrating agent or activating agent. The use of ionic liquids as supports as well as solvents result in the faster kinetics of the process, the separation issues are reduced, and the process has no racemization issues.
Champacyclin, a new cyclic octapeptide from Streptomyces strain C42 isolated from the Baltic Sea
Pesic, Alexander,Baumann, Heike I.,Kleinschmidt, Katrin,Ensle, Paul,Wiese, Jutta,Suessmuth, Roderich D.,Imhoff, Johannes F.
, p. 4834 - 4857 (2014/02/14)
New isolates of Streptomyces champavatii were isolated from marine sediments of the Gotland Deep (Baltic Sea), from the Urania Basin (Eastern Mediterranean), and from the Kiel Bight (Baltic Sea). The isolates produced several oligopeptidic secondary metabolites, including the new octapeptide champacyclin (1a) present in all three strains. Herein, we report on the isolation, structure elucidation and determination of the absolute stereochemistry of this isoleucine/leucine (Ile/Leu = Xle) rich cyclic octapeptide champacyclin (1a). As 2D nuclear magnetic resonance (NMR) spectroscopy could not fully resolve the structure of (1a), additional information on sequence and configuration of stereocenters were obtained by a combination of multi stage mass spectrometry (MSn) studies, amino acid analysis, partial hydrolysis and subsequent enantiomer analytics with gas chromatography positive chmical ionization/electron impact mass spectrometry (GC-PCI/EI-MS) supported by comparison to reference dipeptides. Proof of the head-to-tail cyclization of (1a) was accomplished by solid phase peptide synthesis (SPPS) compared to an alternatively side chain cyclized derivative (2). Champacyclin (1a) is likely synthesized by a non-ribosomal peptide synthetase (NRPS), because of high content of (D)-amino acids. The compound (1a) showed antimicrobial activity against the phytopathogen Erwinia amylovora causing the fire blight disease of certain plants.
