Spectrum of polysaccharides degradation products of ales and lager beers

The saccharide spectrum, as a distribution of fractions of different molecular mass, of sixteen beers was determined by ultracentrifugation using filters with cut-offs of 1, 5, 10 and 50 kDa. The saccharide concentrations in the filtrates were determined by density measurements. The saccharide composition was examined through HPAEC-PAD. The results were compared with the values of classic features of beers. The newly developed method provides additional information of the beers and is a simple and fast tool for exploring the effect of the saccharide spectrum on the industrial characteristics. The results revealed that similar top fermentation beers and similar lager beers have different saccharide spectra

Allosteric Inhibition of Factor XIIIa. Non-Saccharide Glycosaminoglycan Mimetics, but Not Glycosaminoglycans, Exhibit Promising Inhibition Profile

Factor XIIIa (FXIIIa) is a transglutaminase that catalyzes the last step in the coagulation process. Orthostery is the only approach that has been exploited to design FXIIIa inhibitors. Yet, allosteric inhibition of FXIIIa is a paradigm that may offer a key advantage of controlled inhibition over orthosteric inhibition. Such an approach is likely to lead to novel FXIIIa inhibitors that do not carry bleeding risks. We reasoned that targeting a collection of basic amino acid residues distant from FXIIIa’s active site by using sulfated glycosaminoglycans (GAGs) or non-saccharide GAG mimetics (NSGMs) would lead to the discovery of the first allosteric FXIIIa inhibitors. We tested a library of 22 variably sulfated GAGs and NSGMs against human FXIIIa to discover promising hits. Interestingly, although some GAGs bound to FXIIIa better than NSGMs, no GAG displayed any inhibition. An undecasulfated quercetin analog was found to inhibit FXIIIa with reasonable potency (efficacy of 98%). Michaelis-Menten kinetic studies revealed an allosteric mechanism of inhibition. Fluorescence studies confirmed close correspondence between binding affinity and inhibition potency, as expected for an allosteric process. The inhibitor was reversible and at least 9-fold- and 26-fold selective over two GAG-binding proteins factor Xa (efficacy of 71%) and thrombin, respectively, and at least 27-fold selective over a cysteine protease papain. The inhibitor also inhibited the FXIIIa-mediated polymerization of fibrin in vitro. Overall, our work presents the proof-of-principle that FXIIIa can be allosterically modulated by sulfated non-saccharide agents much smaller than GAGs, which should enable the design of selective and safe anticoagulants

Dendritic glycopolymers based on dendritic polyamine scaffolds: view on their synthetic approaches, characteristics and potential for biomedical applications

In this review we highlight the potential for biomedical applications of dendritic glycopolymers based on polyamine scaffolds. The complex interplay of the molecular characteristics of the dendritic architectures and their specific interactions with various (bio)molecules are elucidated with various examples. A special role of the individual sugar units attached to the dendritic scaffolds and their density is identified, which govern ionic and H-bond interactions, and biological targeting, but to a large extent are also responsible for the significantly reduced toxicity of the dendritic glycopolymers compared to their polyamine scaffolds. Thus, the application of dendritic glycopolymers in drug delivery systems for gene transfection but also as therapeutics in neurodegenerative diseases has great promisePublikacja w ramach programu Royal Society of Chemistry "Gold for Gold" 2014 finansowanego przez Uniwersytet Łódzk

Lipopolysaccharide-specific acyloxyacyl hydrolase

" An acyloxyacyl hydrolase from the human promyelocyte cell line HL-60 has been found to specifically hydrolyze fatty acids from their ester linkages to hydroxy groups of 3-hydroxyfatty acids, the latter being being bound in turn to lipopolysaccharide glycosaminyl residues. The hydrolyzed fatty acids may include dodecanoic acid, tetradecanoic acid and hexadecanoic acid. This enzyme showed a molecular weight by gel exclusion chromatography between about 50,000 Daltons and about 70,000 Daltons, and a molecular weight by polyacrylamide gel electrophoresis with sodium dodecylsulphate, using reduced molecular weight standards, of approximately 54,000 to 60,000 Daltons. Altered bacterial lipopolysaccharide substantially without fatty acids bound in ester linkage to hydroxy groups of 3-hydroxyfatty acids covalently linked to a glucosaminyl moiety of lipopolysaccharide lipid A are produced. Since the structure of the lipid A moiety is highly conserved, acyloxyacyl hydrolase may act on lipopolysaccharide of many different pathogenic bacteria (for example Salmonella, Escherichia, Hemophilus, and Neisseria). Such altered bacterial lipopolysaccharide, having toxicity reduced more than immunostimulatory activity, may be therapeutically useful: (1) as vaccines to prevent Gram-negative bacterial diseases by inducing antibodies to lipopolysaccharide O-polysaccharide or R-core antigens, (2) as antidotes to treat or prevent Gram-negative bacterial sepsis (""septic shock""), or (3) as adjuvants to enhance formation of antibodies to other antigens. the acyloxyacyl hydrolase itself may be prophylactically or therapeutically useful to detoxify endogenous lipopolysaccharide in patients with Gram-negative bacterial diseases. The enzyme may also be used to remove toxic lipopolysaccharide from therapeutic injectants. "Board of Regents, University of Texas Syste

The biofilm matrix of Pseudomonas sp. OX1 grown on phenol is mainly constituted by alginate oligosaccharides

The structure of the major constituent of the biofilm matrix produced by Pseudomonas sp. OX1, when grown on phenol as the sole carbon source is described. This investigation, carried out by chemical analysis, NMR spectroscopy and MALDI-TOF MS spectrometry, showed the presence of an oligosaccharide blend with the typical alginate structure, namely (1-->4) substituted beta-D-mannuronic (ManA) and alpha-L-guluronic acid (GulA). GulA residues were non-acetylated whereas ManA was always O-acetylated at C-2 or C-3

Resuscitation-promoting factors possess a lysozyme-like domain

The novel bacterial cytokine family – resuscitation-promoting factors (Rpfs) – share a conserved domain of uncharacterized function. Predicting the structure of this domain suggests that Rpfs possess a lysozyme-like domain. The model highlights the good conservation of residues involved in catalysis and substrate binding. A lysozyme-like function makes sense for this domain in the light of experimental characterization of the biological function of Rpfs

Substrate-Assisted Catalysis Unifies Two Families of Chitinolytic Enzymes

Hen egg-white lysozyme has long been the paradigm for enzymatic glycosyl hydrolysis with retention of configuration, with a protonated carboxylic acid and a deprotonated carboxylate participating in general acid-base catalysis. In marked contrast, the retaining chitin degrading enzymes from glycosyl hydrolase families 18 and 20 all have a single glutamic acid as the catalytic acid but lack a nucleophile on the enzyme. Both families have a catalytic (βα)8-barrel domain in common. X-ray structures of three different chitinolytic enzymes complexed with substrates or inhibitors identify a retaining mechanism involving a protein acid and the carbonyl oxygen atom of the substrate’s C2 N-acetyl group as the nucleophile. These studies unambiguously demonstrate the distortion of the sugar ring toward a sofa conformation, long postulated as being close to that of the transition state in glycosyl hydrolysis.

INVESTIGATION OF ANTICOAGULATION PROPERTIES OF SULFATED GLYCOSAMINOGLYCAN MIMETICS

Abstract INVESTEGATION OF ANTICOAGULATION PROPERTIES OF SULFATED GLYCOSAMINOGLYCAN MIMETICS By Elsamani Ismail Abdelfadiel, MS A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University Virginia Commonwealth University, 2017. Supervisor: Umesh R Desai Professor, Department of Medicinal Chemistry The existence of thrombosis in numerous pathophysiological situations formed a vast necessity for anticoagulation therapy. Thrombin and factor Xa are the only two factors of the entire coagulation cascade that have been major targets for regulation of clotting via the direct and indirect mechanism of inhibition. Our recent discovery of sulfated non-saccharide glycosaminoglycan mimetics, especially G2.2, that demonstrates highly selective cancer stem-like cells (CSCs) inhibition activity. G2.2 inhibited the growth of CSCs from multiple cancer cell lines. To evaluate its in vivo anticoagulation effect, we asked a contract research organization (CRO) to produce 20 g of material, labelled as G2.2Y. Evaluation of G2.2C in HT-29 xenograft mouse model showed a significant reduction in tumor volume and CSC markers, but unexpected bleeding consequences in some animals were observed. Also in a tail bleeding experiment, G2.2Y showed a significant enhancement in bleeding volume. Comparable studies with G2.2 synthesized in our laboratory had shown no bleeding effects. To investigate the difference between the two G2.2 samples (G2.2W (white) and G2.2Y (Yellow) that were performed using UPLC-MS characterization, we were able to determine that the G2.2Y sample was an 85:15 blend of two compounds. Elemental, NMR and MS data revealed that G2.2W was fully sulfated flavonoid derivative, as expected, but G2.2Y contained one less sulfate group. We tested both agents for their inhibition of various coagulation factors and revealed that G2.2Y inhibited fXIa nearly 2-fold better in comparison to G2.2W. Furthermore, activated partial thromboplastin time assay (APTT) indicated that G2.2W exhibited almost 3-4-fold less anticoagulant activity compared to G2.2Y. This indicates that the loss of just one sulfate group could induce substantial side effects and lead to a discovery of new anticoagulant agent. Such structure–activity relationship is important to understand if the in vivo metabolism of the agents leads to accumulation of de-sulfated products