Search results for "Dipeptides"
showing 10 items of 49 documents
A synthetic method for diversification of the P1′ substituent in phosphinic dipeptides as a tool for exploration of the specificity of the S1′ bindin…
2007
Abstract A novel, general, and versatile method of diversification of the P1′ position in phosphinic pseudodipeptides, presumable inhibitors of proteolytic enzymes, was elaborated. The procedure was based on parallel derivatization of the amino group in the suitably protected phosphinate building blocks with appropriate alkyl and aryl halides. This synthetic strategy represents an original approach to phosphinic dipeptide chemistry. Its usefulness was confirmed by obtaining a series of P1′ modified phosphinic dipeptides, inhibitors of cytosolic leucine aminopeptidase, through computer-aided design basing on the structure of homophenylalanyl-phenylalanine analogue (hPheP[CH 2 ]Phe) bound in …
Toward very potent, non-covalent organophosphonate inhibitors of cathepsin C and related enzymes by 2-amino-1-hydroxy-alkanephosphonates dipeptides
2013
Cathepsins play an important role in several human disorders and therefore the design and synthesis of their inhibitors attracts considerable interest in current medicinal chemistry approaches. Due to the presence of a strong sulphydryl nucleophile in the active center of the cysteine type cathepsins, most strategies to date have yielded covalent inhibitors. Here we present a series of non-covalent β-amino-α-hydroxyalkanephosphonate dipeptidic inhibitors of cathepsin C, ranking amongst the best low-molecular weight inhibitors of this enzyme. Their binding modes determined by molecular modelling indicate that the hydroxymethyl fragment of the molecule, not the phosphonate moiety, acts as a t…
Microvesicles shed by oligodendroglioma cells and rheumatoid synovial fibroblasts contain aggrecanase activity
2012
Membrane microvesicle shedding is an active process and occurs in viable cells with no signs of apoptosis or necrosis. We report here that microvesicles shed by oligodendroglioma cells contain an ‘aggrecanase’ activity, cleaving aggrecan at sites previously identified as targets for adamalysin metalloproteinases with disintegrin and thrombospondin domains (ADAMTSs). Degradation was inhibited by EDTA, the metalloproteinase inhibitor GM6001 and by tissue inhibitor of metalloproteinases (TIMP)-3, but not by TIMP-1 or TIMP-2. This inhibitor profile indicates that the shed microvesicles contain aggrecanolytic ADAMTS(s) or related TIMP-3-sensitive metalloproteinase(s). The oligodendroglioma cells…
Clinical Translation and First In-Human Use of [44Sc]Sc-PSMA-617 for PET Imaging of Metastasized Castrate-Resistant Prostate Cancer
2017
Background: Various trivalent radiometals are well suited for labeling of DOTA-conjugated variants of Glu-ureido-based prostate-specific membrane antigen (PSMA) inhibitors. The DOTA-conjugate PSMA-617 has proven high potential in PSMA radioligand therapy (PSMA-RLT) of prostate cancer as well as PET imaging when labeled with lutetium-177 and gallium-68 respectively. Considering the relatively short physical half-life of gallium-68 this positron emitter precludes prolonged acquisition periods, as required for pre-therapeutic dosimetry or intraoperative applications. In this context, the positron emitter scandium-44 is an attractive alternative for PET imaging. We report the synthesis of [44Sc…
A structural insight into the P1 S1 binding mode of diaminoethylphosphonic and phosphinic acids, selective inhibitors of alanine aminopeptidases
2016
Abstract N′-substituted 1,2-diaminoethylphosphonic acids and 1,2-diaminoethylphosphinic dipeptides were explored to unveil the structural context of the unexpected selectivity of these inhibitors of M1 alanine aminopeptidases (APNs) versus M17 leucine aminopeptidase (LAP). The diaminophosphonic acids were obtained via aziridines in an improved synthetic procedure that was further expanded for the phosphinic pseudodipeptide system. The inhibitory activity, measured for three M1 and one M17 metalloaminopeptidases of different sources (bacterial, human and porcine), revealed several potent compounds (e.g., K i = 65 nM of 1u for Hs APN). Two structures of an M1 representative (APN from Neisser…
Unnatural amino acids increase activity and specificity of synthetic substrates for human and malarial cathepsin C
2014
Mammalian cathepsin C is primarily responsible for the removal of N-terminal dipeptides and activation of several serine proteases in inflammatory or immune cells, while its malarial parasite ortholog dipeptidyl aminopeptidase 1 plays a crucial role in catabolizing the hemoglobin of its host erythrocyte. In this report, we describe the systematic substrate specificity analysis of three cathepsin C orthologs from Homo sapiens (human), Bos taurus (bovine) and Plasmodium falciparum (malaria parasite). Here, we present a new approach with a tailored fluorogenic substrate library designed and synthesized to probe the S1 and S2 pocket preferences of these enzymes with both natural and a broad ran…
Relative contribution of different l-arginine sources to the substrate supply of endothelial nitric oxide synthase
2011
In certain cases of endothelial dysfunction l-arginine becomes rate-limiting for NO synthesis in spite of sufficiently high plasma concentrations of the amino acid. To better understand this phenomenon, we investigated routes of substrate supply to endothelial nitric oxide synthase (eNOS). Our previous data with human umbilical vein (HUVEC) and EA.hy.926 endothelial cells demonstrated that eNOS can obtain its substrate from the conversion of l-citrulline to l-arginine and from protein breakdown. In the present study, we determined the quantitative contribution of proteasomal and lysosomal protein degradation and investigated to what extent extracellular peptides and l-citrulline can provide…
Immunoproteasome and Non-Covalent Inhibition: Exploration by Advanced Molecular Dynamics and Docking Methods
2021
The selective inhibition of immunoproteasome is a valuable strategy to treat autoimmune, inflammatory diseases, and hematologic malignancies. Recently, a new series of amide derivatives as non-covalent inhibitors of the β1i subunit with Ki values in the low/submicromolar ranges have been identified. Here, we investigated the binding mechanism of the most potent and selective inhibitor, N-benzyl-2-(2-oxopyridin-1(2H)-yl)propanamide (1), to elucidate the steps from the ligand entrance into the binding pocket to the ligand-induced conformational changes. We carried out a total of 400 ns of MD-binding analyses, followed by 200 ns of plain MD. The trajectories clustering allowed identifying thre…
Individual stereoisomers of phosphinic dipeptide inhibitor of leucine aminopeptidase
2008
Abstract Individual stereoisomers of the phosphinic pseudodipeptide hPheψ[P(O)(OH)CH2]Phe were obtained by stereoselective liquid chromatographic separation as N- and C-terminally protected derivative on quinidine carbamate modified silica stationary phase. The stereoisomeric purity, exceeding 95% for each fraction, was determined before and after deprotection using two independent methods. The absolute configuration was rationally assigned by application of enantiomerically pure phosphinic acid substrates in the synthetic procedure and correlation with biological activity of the products. Substantial differences in inhibition of leucine aminopeptidase by the individual isomers revealed nov…
Unusual activity pattern of leucine aminopeptidase inhibitors based on phosphorus containing derivatives of methionine and norleucine
2010
Ligands containing bulky aliphatic P1 residues exhibit a high affinity towards cytosolic leucine aminopeptidase, a bizinc protease of biomedical significance. According to this specificity, a series of phosphonic and phosphinic compounds have been put forward as novel putative inhibitors of the enzyme. These phosphonic and phosphinic compounds were derivatives of methionine and norleucine as both single amino acids and dipeptides. The designed inhibitors were synthesised and tested towards the peptidase isolated from porcine kidneys using an improved separation procedure affording superior homogeneity. Unexpectedly, organophosphorus derivatives of methionine and norleucine exhibited moderat…