282727-46-2Relevant academic research and scientific papers
Simplified determination of the content and average degree of acetylation of chitin in crude black soldier fly larvae samples
D'Hondt, Els,Soetemans, Lise,Bastiaens, Leen,Maesen, Miranda,Jespers, Vincent,Van den Bosch, Bert,Voorspoels, Stefan,Elst, Kathy
supporting information, (2020/01/25)
Insects are considered a promising alternative protein source for food and feed, but contain significant amounts of chitin, often undesirable due to indigestibility, disagreeable texture and negative effect on nutrients intake. Fractionation strategies are thus increasingly being applied to isolate and valorize chitin separately. The analysis of chitin generally requires an intensive pretreatment to remove impurities, and derivatization to generate sufficient detector response. In this work, a liquid chromatography method, without pretreatment nor derivatization, was developed for the simultaneous determination of chitin content and degree of acetylation in non-purified samples of black soldier fly (BSF) larvae. The method is found to be more suitable, compared to traditional methods, for assessing high degrees of acetylation. For the first time, the degree of acetylation of BSF chitin (81 ± 2%) is reported. Additionally, the chitin content of BSF soft tissues is estimated at approximately 20% of the total chitin content (8.5 ± 0.1%).
N-acetyltransferases from three different organisms displaying distinct selectivity toward hexosamines and N-terminal amine of peptides
Zhang, Peiru,Liu, Pei,Xu, Yangyang,Liang, Yulu,Wang, Peng George,Cheng, Jiansong
, p. 72 - 75 (2018/11/30)
N-acetyltransferases are a family of enzymes that catalyze the transfer of the acetyl moiety (–COCH3) from acetyl coenzyme A (Acetyl-CoA) to a primary amine of acceptor substrates from small molecules such as aminoglycoside to macromolecules of various proteins. In this study, the substrate selectivity of three N-acetyltransferases falling into different phylogenetic groups was probed against a series of hexosamines and synthetic peptides. GlmA from Clostridium acetobutylicum and RmNag from Rhizomucor miehei, which have been defined as glucosamine N-acetyltransferases, were herein demonstrated to be also capable of acetylating the free amino group on the very first glycine residue of peptide in spite of varied catalytic efficiency. The human recombinant N-acetyltransferase of Naa10p, however, prefers primary amine groups in the peptides as opposed to glucosamine. The varied preference of GlmA, RmNag and Naa10p probably arose from the divergent evolution of these N-acetyltransferases. The expanded knowledge of acceptor specificity would as well facilitate the application of these N-acetyltransferases in the acetylation of hexosamines or peptides.
Escherichia coli O106, a new member of a group of enteric bacteria sharing an O-polysaccharide backbone structure
Shashkov,Senchenkova,Naumenko,Kalinchuk,Perepelov,Knirel, Yu. A.
, p. 1538 - 1541 (2018/10/31)
O-Polysaccharides (O-antigens) of a number of genetically related Escherichia coli O-serogroups (O17, O44, O73, O77, and O106) and Salmonella enterica O:6,14 possess an identical main chain composed of d-GlcNAc and d-Man residues and differ from each other by the absence or presence of glucose side chains at various positions. Using two-dimensional NMR spectroscopy, we established the structure of the O-polysaccharide of E. coli O106 having two glucose side chains in a hexasaccharide repeating unit.
Process optimization, purification and characterization of a novel acidic, thermostable chitinase from Humicola grisea
Kumar, Manish,Brar, Amandeep,Vivekanand,Pareek, Nidhi
, p. 931 - 938 (2018/05/29)
An extracellular acidic and thermostable chitinase (HgChi) from thermophilic Humicola grisea was purified and characterized. Enhancement in chitinase production (Qp = 2.9662 Ul?1 h?1) was achieved through derivation of optimum fermentation conditions via central composite design. H. grisea observed to produce various isoforms of chitinase, among which the major expressed form has molecular mass of about 50 kDa. Purified chitinases exhibited optimal activity at pH 3.0 and 70 °C. Chitinase showed notable stability at increasing temperatures. Half-life of chitinase is 169.06 min at optimum temperature. Chitinase has effectively catalyzed N-acetyl chitobiose (GlcNAc)2, and N-acetyl chitotriose (GlcNAc)3 and colloidal chitin. Purified chitinase from H. grisea showed high affinity towards colloidal chitin as evident by its comparatively lower Km value. Presence of metal ions viz. Mn2+, Co2+, NH4 + and Mg2+ significantly increased the chitinase activity. Thin layer chromatography (TLC) analysis revealed the significant hydrolyzing competence of HgChi for colloidal chitin, (GlcNAc)3 and (GlcNAc)2 into oligomers and N-acetyl–D-glucosamine (GlcNAc). Thermostable chitinase appeared as potential candidate for efficient conversion of chitin to bioactive oligosaccharides at industrial scale.
Pro-apoptotic activity of acylated triterpenoid saponins from the stem bark of Albizia chevalieri harms
Noté, Olivier Placide,Messi, Lin Marcellin,Mbing, Joséphine Ngo,Azouaou, Sarah Ali,Sarr, Mamadou,Guillaume, Dominique,Muller, Christian Dominique,Pegnyemb, Dieudonné Emmanuel,Lobstein, Annelise
, p. 95 - 101 (2017/10/05)
As a continuation of our interest in apoptosis-inducing triterpenoid saponins from Albizia genus, phytochemical investigation of the stem bark of Albizia chevalieri led to the isolation of three new oleanane-type saponins, named chevalierosides A–C (1–3). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H-, 13C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence. The pro-apoptotic effect of the three saponins was evaluated on two human cell lines (pancreatic carcinoma AsPC-1 and hematopoietic monocytic THP-1). Cytometric analyses showed that saponins 1–3 induced apoptosis of both human cell lines (AsPC-1 and THP-1) in a dose-dependent manner.
The α-Thioglycoligase Derived from a GH89 α-N-Acetylglucosaminidase Synthesises α-N-Acetylglucosamine-Based Glycosides of Biomedical Interest
Tshililo, Ndivhuwo Olga,Strazzulli, Andrea,Cobucci-Ponzano, Beatrice,Maurelli, Luisa,Iacono, Roberta,Bedini, Emiliano,Corsaro, Maria Michela,Strauss, Erick,Moracci, Marco
supporting information, p. 663 - 676 (2017/02/23)
We report here on the preparation of a novel α-thioglycoligase that can be used for the fast and efficient synthesis of α-N-acetylglucosamine-based glycosides. Using the α-N-acetyl-glucosaminidase from Clostridium perfringens of family GH89 (according to the Carbohydrate Active Enzymes classification) as starting point, we prepared mutants in the acid/base residue glutamic acid 483 that were found to have different synthetic efficiencies (maximal yields >80% after 24 h) in the presence of an activated donor and suitable acceptors. The synthetic potential of the Glu483 alanine mutant as an α-thioglycoligase – only the third biocatalyst with this stereospecificity reported to date, and the first selective for the N-acetylglucosamine moiety – was demonstrated by producing for the first time N-acetyl-α-d-glucosaminyl azide and N-acetylglucosamine α-thioglycosides in high yields. To showcase the application of such compounds, we show that they offer the wild-type CpGH89 protection from thermal unfolding, demonstrating their potential as pharmacological chaperones for the treatment of mucopolysaccharidosis IIIB (Sanfilippo syndrome). (Figure presented.).
Cytotoxic Oleanane-Type Saponins from the Leaves of Albizia anthelmintica Brongn.
Al-Sayed, Eman,Eldahshan, Omayma A.,Bahgat, Dina M.,Singab, Abdel Nasser B.
, p. 1666 - 1673 (2016/12/14)
Two new oleanane-type saponins: β-d-xylopyranosyl-(1 → 4)-6-deoxy-α-l-mannopyranosyl-(1 → 2)-1-O-{(3β)-28-oxo-3-[(2-O-β-d-xylopyranosyl-β-d-glucopyranosyl)oxy]olean-12-en-28-yl}-β-d-glucopyranose (1) and 1-O-[(3β)-28-oxo-3-{[β-d-xylopyranosyl-(1 → 2)-α-l-
Unusual Cytotoxic Steroidal Saponins from the Gorgonian Astrogorgia dumbea
Lu, Ya-Nan,Cui, Ping,Tian, Xiao-Qing,Lou, Li-Guang,Fan, Cheng-Qi
, p. 882 - 887 (2016/07/11)
Three steroidal saponins, including astrogorgiosides A (1) and B (2) bearing acetamido-glucose moieties, and astrogorgioside C (3) with a 19-nor and bearing an aromatized B ring steroid aglycone, together with a known major saponin dimorphoside A (4), were obtained from the gorgonian Astrogorgia dumbea collected near Dongshan Island in East China Sea. Structures of these compounds were elucidated by in-depth spectral and chemical methods, including 2D-NMR, HR-ESI-MS spectra, and acidic hydrolysis. For the first time, acetamido-glucose moiety is being reported from a gorgonian. The B-ring aromatized steroid aglycone of compound 3 is also rare in marine natural products. Compounds 1-3 exhibited moderate cytotoxic activity with IC50 values of 26.8-45.6 μM against human tumor cells Bel-7402 and K562.
Structural Insights into the Recovery of Aldolase Activity in N-Acetylneuraminic Acid Lyase by Replacement of the Catalytically Active Lysine with γ-Thialysine by Using a Chemical Mutagenesis Strategy
Timms, Nicole,Windle, Claire L.,Polyakova, Anna,Ault, James R.,Trinh, Chi H.,Pearson, Arwen R.,Nelson, Adam,Berry, Alan
, p. 474 - 481 (2013/05/08)
Chemical modification has been used to introduce the unnatural amino acid γ-thialysine in place of the catalytically important Lys165 in the enzyme N-acetylneuraminic acid lyase (NAL). The Staphylococcus aureus nanA gene, encoding NAL, was cloned and expressed in E. coli. The protein, purified in high yield, has all the properties expected of a class I NAL. The S. aureus NAL which contains no natural cysteine residues was subjected to site-directed mutagenesis to introduce a cysteine in place of Lys165 in the enzyme active site. Subsequently chemical mutagenesis completely converted the cysteine into γ-thialysine through dehydroalanine (Dha) as demonstrated by ESI-MS. Initial kinetic characterisation showed that the protein containing γ-thialysine regained 17% of the wild-type activity. To understand the reason for this lower activity, we solved X-ray crystal structures of the wild-type S. aureus NAL, both in the absence of, and in complex with, pyruvate. We also report the structures of the K165C variant, and the K165-γ-thialysine enzyme in the presence, or absence, of pyruvate. These structures reveal that γ-thialysine in NAL is an excellent structural mimic of lysine. Measurement of the pH-activity profile of the thialysine modified enzyme revealed that its pH optimum is shifted from 7.4 to 6.8. At its optimum pH, the thialysine-containing enzyme showed almost 30% of the activity of the wild-type enzyme at its pH optimum. The lowered activity and altered pH profile of the unnatural amino acid-containing enzyme can be rationalised by imbalances of the ionisation states of residues within the active site when the pKa of the residue at position 165 is perturbed by replacement with γ-thialysine. The results reveal the utility of chemical mutagenesis for the modification of enzyme active sites and the exquisite sensitivity of catalysis to the local structural and electrostatic environment in NAL.
Antitumor and immunomodulatory activities of a polysaccharide from Artemisia argyi
Bao, Xiaoli,Yuan, Huihui,Wang, Chengzhong,Liu, Jinjin,Lan, Minbo
, p. 1236 - 1243 (2013/10/22)
A water-soluble polysaccharide (FAAP-02), composed of N-acetyl-d- glucosamine, glucose, mannose, galactose, rhamnose arabinose, xylose and ribose, with an average molecular weight of 5169 Da, was isolated from Artemisia argyi. The antitumor and immunomodulatory activities of FAAP-02 were evaluated in Sarcoma 180 (S180) tumor-bearing mice by intraperitoneal administration. As a result, FAAP-02 significantly inhibited the growth of the S180 transplanted tumors and prolonged the survival time of the tumor-bearing mice. Moreover, FAAP-02 could obviously increase the thymus and spleen indices, the levels of serum Interleukin 2 (IL-2), Interleukin 6 (IL-6), Interleukin 12 (IL-12) and tumor necrosis factor- α (TNF-α) and the expression of CD4+ and CD8+ splenic T lymphocytes which were suppressed by the transplanted tumor or/and 5-fluorouracil (5-FU) in the mice. These results indicated that the antitumor activity of FAAP-02 might be associated with its immunostimulatory effects.
