scholarly journals Enzyme Properties of a Laccase Obtained from the Transcriptome of the Marine-Derived Fungus Stemphylium lucomagnoense

2020 ◽  
Vol 21 (21) ◽  
pp. 8402
Author(s):  
Wissal Ben Ali ◽  
Amal Ben Ayed ◽  
Annick Turbé-Doan ◽  
Emmanuel Bertrand ◽  
Yann Mathieu ◽  
...  

Only a few studies have examined how marine-derived fungi and their enzymes adapt to salinity and plant biomass degradation. This work concerns the production and characterisation of an oxidative enzyme identified from the transcriptome of marine-derived fungus Stemphylium lucomagnoense. The laccase-encoding gene SlLac2 from S. lucomagnoense was cloned for heterologous expression in Aspergillus niger D15#26 for protein production in the extracellular medium of around 30 mg L−1. The extracellular recombinant enzyme SlLac2 was successfully produced and purified in three steps protocol: ultrafiltration, anion-exchange chromatography, and size exclusion chromatography, with a final recovery yield of 24%. SlLac2 was characterised by physicochemical properties, kinetic parameters, and ability to oxidise diverse phenolic substrates. We also studied its activity in the presence and absence of sea salt. The molecular mass of SlLac2 was about 75 kDa, consistent with that of most ascomycete fungal laccases. With syringaldazine as substrate, SlLac2 showed an optimal activity at pH 6 and retained nearly 100% of its activity when incubated at 50°C for 180 min. SlLac2 exhibited more than 50% of its activity with 5% wt/vol of sea salt.

Author(s):  
Ken-ji Yokoi ◽  
Sosyu Tsutsui ◽  
Gen-ya Arakawa ◽  
Masakazu Takaba ◽  
Koichi Fujii ◽  
...  

Abstract Information about the inulosucrase of non-lactic acid bacteria is scarce. We found a gene encoding inulosucrase (inuBK) in the genome of the gram-positive bacterium Alkalihalobacillus krulwichiae JCM 11691. The inuBK open reading frame encoded a protein comprising 456 amino acids. We expressed His-tagged InuBK in culture medium using a Brevibacillus system. The optimal pH and temperature of purified InuBK were 7.0–9.0 and 50 °C–55 °C, respectively. The findings of high-performance anion-exchange chromatography, nuclear magnetic resonance spectroscopy, and high-performance size-exclusion chromatography with multi-angle laser light scattering showed that the polysaccharide produced by InuBK was an inulin with a molecular weight of 3,806, a polydispersity index (PI) of 1.047, and fructosyl chain lengths with 3–27 degrees of polymerization. The size of InuBK was smaller than commercial inulins, and the PI of the inulin that it produced was lower.


2020 ◽  
Vol 10 (8) ◽  
pp. 2648 ◽  
Author(s):  
Paolina Lukova ◽  
Mariana Nikolova ◽  
Emmanuel Petit ◽  
Redouan Elboutachfaiti ◽  
Tonka Vasileva ◽  
...  

The aim of the present study was to evaluate the prebiotic potential of Plantago major L. leaves water-extractable polysaccharide (PWPs) and its lower molecular fractions. The structure of PWPs was investigated by high pressure anion exchange chromatography (HPAEC), size exclusion chromatography coupled with multi-angle laser light scattering detector (SEC-MALLS) and Fourier-transform infrared (FTIR) spectroscopy. The chemical composition and monosaccharide analyses showed that galacturonic acid was the main monosaccharide of PWPs followed by glucose, arabinose, galactose, rhamnose and xylose. FTIR study indicated a strong characteristic absorption peak at 1550 cm−1 corresponding to the vibration of COO− group of galacturonic acid. The PWPs was subjected to hydrolysis using commercial enzymes to obtain P. major low molecular fraction (PLM) which was successively separated by size exclusion chromatography on Biogel P2. PWPs and PLM were examined for in vitro prebiotic activity using various assays. Results gave evidence for changes in optical density of the bacteria cells and pH of the growth medium. A heterofermentative process with a lactate/acetate ratio ranged from 1:1 to 1:5 was observed. The ability of PLM to stimulate the production of certain probiotic bacteria glycohydrolases and to be fermented by Lactobacillus sp. strains was successfully proved.


Holzforschung ◽  
2004 ◽  
Vol 58 (1) ◽  
pp. 97-104 ◽  
Author(s):  
B. Saake ◽  
S. Lebioda ◽  
J. Puls

Abstract Four methyl cellulose samples in the degree of substitution range from 0.5 to 2.0 were characterised by combination of different analytical methods. Samples were analysed regarding their partial degree of substitution by hydrolysis and anion exchange chromatography with pulsed amperometric detection. For calibration of the chromatographic system, standard substances were isolated by preparative HPLC and their structure was confirmed by 13C-NMR spectroscopy. For two methyl cellulose samples per-acetylation and 13C-NMR with inverse gated decoupling was carried out for comparison with the chromatographic analysis. Endoglucanase fragmentation of methyl celluloses was performed and water-soluble and insoluble fractions were analysed separately. A preparative size exclusion chromatography system for enzymatic-degraded water-soluble methyl cellulose was developed and the molar masses of the individual fractions were examined by analytical size exclusion chromatography. By combination of endoglucanase fragmentation, preparative chromatography, hydrolysis and anion exchange chromatography an approach for the analysis of the substitutent distribution along the polymeric chain of water-soluble methyl cellulose could be established.


2018 ◽  
Vol 13 (6) ◽  
pp. 1934578X1801300
Author(s):  
Heng Long Wang ◽  
Chin Wei Tu ◽  
Wei Zhi Wu ◽  
Chen Yi Lin ◽  
Su Yu Chen ◽  
...  

An acidic mucilage was isolated from the outer-layer seed coat of shaddock (Citrus grandis Osbeck) by water extraction at room temperature, and purified by DE-52 anion-exchange chromatography using 0.26 – 0.37 M NaCl. This purified mucilage was almost entirely composed of galacturonic acid residues. Glycosyl-linkage analysis showed that the backbone was 1→4 linked. Fourier Transform Infrared Spectroscopic analysis and determination of the degree of methylation further revealed that the mucilage was a low-degree (11.94%) esterified homogalacturonan. Size exclusion chromatography showed that the major molecular weight distribution of 610.9 kDa.


1994 ◽  
Vol 49 (5-6) ◽  
pp. 293-301 ◽  
Author(s):  
Cornelia Fuchs ◽  
Gerd Hansen

Abstract Lipase (triacylglycerol acylhydrolase EC 3.1.1.3) from rape (Brassica napus cv. Ceres) was isolated from cotyledons of dark-grown seedlings. The enzyme was partially purified by poly­ ethylene glycol precipitation. Delipidation of the lipase with n-hexane was required prior to further purification by anion exchange chromatography and size exclusion chromatography. A purification factor of 337 was ultimately achieved and the purification process was moni­tored by SDS-PAGE. Here, at least two protein bands with molecular masses of 62 and 64 kD a respectively were found in the active fraction obtained by size exclusion chromatography. Sodium deoxycholate was found to stimulate the lipase activity, but appeared to cause aggregation of the enzyme. It was not possible to estimate the isoelectric point of the dialyzed rape lipase due to the high molecular mass of the aggregates. Two simple methods to detect lipase activity directly on polyacrylamide gel were applied. No esterase activity was found by using p-nitrophenyl acetate as substrate.


2006 ◽  
Vol 395 (2) ◽  
pp. 319-329 ◽  
Author(s):  
Synnøve Holtan ◽  
Per Bruheim ◽  
Gudmund Skjåk-Bræk

AlgE1, AlgE5 and AlgE6 are members of a family of mannuronan C-5 epimerases encoded by the bacterium Azotobacter vinelandii, and are active in the biosynthesis of alginate, where they catalyse the post-polymerization conversion of β-D-mannuronic acid (M) residues into α-L-guluronic acid residues (G). All enzymes show preference for introducing G-residues neighbouring a pre-existing G. They also have the capacity to convert single M residues flanked by G, thus ‘condensing’ G-blocks to form almost homopolymeric guluronan. Analysis of the length and distribution of G-blocks based on specific enzyme degradation combined with size-exclusion chromatography, electrospray ionization MS, HPAEC–PAD (high-performance anion-exchange chromatography and pulsed amperometric detection), MALDI (matrix-assisted laser-desorption ionization)-MS and NMR revealed large differences in block length and distribution generated by AlgE1 and AlgE6, probably reflecting their different degree of processivity. When acting on polyMG as substrates, AlgE1 initially forms only long homopolymeric G-blocks >50, while AlgE6 gives shorter blocks with a broader block size distribution. Analyses of the AlgE1 and AlgE6 subsite specificities by the same methodology showed that a mannuronan octamer and heptamer respectively were the minimum substrate chain lengths needed to accommodate enzyme activities. The fourth M residue from the non-reducing end is epimerized first by both enzymes. When acting on MG-oligomers, AlgE1 needed a decamer while AlgE6 an octamer to accommodate activity. By performing FIA (flow injection analysis)-MS on the lyase digests of epimerized and standard MG-oligomers, the M residue in position 5 from the non-reducing end was preferentially attacked by both enzymes, creating an MGMGGG-sequence (underlined and boldface indicate the epimerized residue).


Author(s):  
Essam M. Ahmed ◽  
Abdelhamid A. Hamdy ◽  
Bandar M. Alshehri

Background: The marine algae are considered a diverse source of bioactive compounds. Many active compounds have been isolated from algae and show good biological activities. Materials and Methods: The aim of this study is to detect the antiviral and anticancer activities in some extracts of marine algae. Extraction, purification and identification of some marine algae common in Egypt were conducted. Extraction of Ulva lactuca, Sargassum dentifolium, and Cystoseiara myrica was conducted. A sequence of extractions, including extraction by ethanol, boiling water, hydrochloric acid and sodium hydroxide were carried out. The obtained extracts were evaluated for their antitumour and antiviral activities against liver tumour cells, brain tumour cell lines, measles virus, mumps virus and hepatitis B virus (HBV). The extracts of the best activities were subjected for purification by size exclusion chromatography and anion exchange chromatography for ethanolic extracts or precipitation by cetylpyridinium chloride (CPC) then by size exclusion chromatography and anion exchange chromatography for aqueous extracts. Separation by GLS/MS was performed. The structures of the active compounds have been identified through different chemical analyses, including sugar analysis, configurational analysis, high-performance liquid chromatography (HPLC), infrared spectroscopy (IR), gas-liquid chromatography-mass spectroscopy (GLC-MS) and 1H,13C nuclear magnetic resonance (NMR) at ZV. Results: The active compounds from the water extracts have been identified mainly as polysaccharides and sulphated polysaccharides. The antitumour and the antiviral activities of ethanolic extracts are attributable to compound identified as Ethyl Palmitate. These natural compounds did not show cytotoxic effect. Conclusion: These outputs could be preliminary for further biological studies aiming to therapeutic application.


1998 ◽  
Vol 64 (7) ◽  
pp. 2479-2484 ◽  
Author(s):  
Venkateswarlu Kadiyala ◽  
Jim C. Spain

ABSTRACT Bacteria that metabolize p-nitrophenol (PNP) oxidize the substrate to 3-ketoadipic acid via either hydroquinone or 1,2,4-trihydroxybenzene (THB); however, initial steps in the pathway for PNP biodegradation via THB are unclear. The product of initial hydroxylation of PNP could be either 4-nitrocatechol or 4-nitroresorcinol. Here we describe the complete pathway for aerobic PNP degradation by Bacillus sphaericus JS905 that was isolated by selective enrichment from an agricultural soil in India. Washed cells of PNP-grown JS905 released nitrite in stoichiometric amounts from PNP and 4-nitrocatechol. Experiments with extracts obtained from PNP-grown cells revealed that the initial reaction is a hydroxylation of PNP to yield 4-nitrocatechol. 4-Nitrocatechol is subsequently oxidized to THB with the concomitant removal of the nitro group as nitrite. The enzyme that catalyzed the two sequential monooxygenations of PNP was partially purified and separated into two components by anion-exchange chromatography and size exclusion chromatography. Both components were required for NADH-dependent oxidative release of nitrite from PNP or 4-nitrocatechol. One of the components was identified as a reductase based on its ability to catalyze the NAD(P)H-dependent reduction of 2,6-dichlorophenolindophenol and nitroblue tetrazolium. Nitrite release from either PNP or 4-nitrocatechol was inhibited by the flavoprotein inhibitor methimazole. Our results indicate that the two monooxygenations of PNP to THB are catalyzed by a single two-component enzyme system comprising a flavoprotein reductase and an oxygenase.


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