共查询到20条相似文献,搜索用时 203 毫秒
1.
J. Rath Robert Messner Paul Kosma Friedrich Altmann Leopold März Christian P. Kubicek 《Archives of microbiology》1995,164(6):414-419
A heteroglycan responsible for the binding of the enzyme β-1,4-d-glucosidase (EC 3.2.1.21) to fungal cell walls was isolated from cell walls of the filamentous fungusTrichoderma reesei. The heteroglycan, composed of mannose, galactose, glucose, and glucuronic acid, also activated β-1,4-d-glucosidase, β-1,4-d-xylosidase andN-acetyl-β-1,4-d-glucosaminidase activity in vitro. The structural backbone of this heteroglycan was prepared by acid hydrolysis and gel filtration.
The molecular structure of the core of the heteroglycan was determined by NMR studies as a linear α-1,6-d-mannan. The mannan core obtained by acid degradation stimulated the β-glucosidase activity by 90%. Several glycosidases fromAspergillus niger were also activated by theT. reesei heteroglycan. The β-glucosidase ofTrichoderma was activated by mannan fromSaccharomyces cerevisiae to a comparable extent. 相似文献
2.
The lytic enzyme active on cell walls ofRhodotorula, which was produced byPenicillium lilacinum ATCC 36010, decomposed an extracellular mannan fromRhodotorula glutinis IFO 0695 and was confined to the β-1,3-mannoside bond on the reducing side of the β-1,4-linkedd-mannopyranose. Based on these results, the structure of the glucomannan, which was a major component ofRhodotorula cell walls, was proposed. 相似文献
3.
Mannanases: microbial sources,production, properties and potential biotechnological applications 总被引:1,自引:0,他引:1
Mannans are the major constituents of the hemicellulose fraction in softwoods and show widespread distribution in plant tissues.
The major mannan-degrading enzymes are β-mannanases, β-mannosidases and β-glucosidases. In addition to these, other enzymes
such as α-galactosidases and acetyl mannan esterases, are required to remove the side chain substituents. The mannanases are
known to be produced by a variety of bacteria, fungi, actinomycetes, plants and animals. Microbial mannanases are mainly extracellular
and can act in wide range of pH and temperature because of which they have found applications in pulp and paper, pharmaceutical,
food, feed, oil and textile industries. This review summarizes the studies on mannanases reported in recent years in terms
of important microbial sources, production conditions, enzyme properties, heterologous expression and potential industrial
applications. 相似文献
4.
A bacterium (strain HC1) capable of assimilating rice bran hemicellulose was isolated from a soil and identified as belonging
to the genus Paenibacillus through taxonomical and 16S rDNA sequence analysis. Strain HC1 cells grown on rice bran hemicellulose as a sole carbon source
inducibly produced extracellular xylanase and intracellular glycosidases such as β-d-glucosidase and β-d-arabinosidase. One of them, β-d-glucosidase was further analyzed. A genomic DNA library of the bacterium was constructed in Escherichia coli and gene coding for β-d-glucosidase was cloned by screening for β-d-glucoside-degrading phenotype in E. coli cells. Nucleotide sequence determination indicated that the gene for the enzyme contained an open reading frame consisting
of 1,347 bp coding for a polypeptide with a molecular mass of 51.4 kDa. The polypeptide exhibits significant homology with
other bacterial β-d-glucosidases and belongs to glycoside hydrolase family 1. β-d-Glucosidase purified from E. coli cells was a monomeric enzyme with a molecular mass of 50 kDa most active at around pH 7.0 and 37°C. Strain HC1 glycosidases
responsible for degradation of rice bran hemicellulose are expected to be useful for structurally determining and molecularly
modifying rice bran hemicellulose and its derivatives. 相似文献
5.
Chomphunuch Songsiriritthigul Bancha Buranabanyat Dietmar Haltrich Montarop Yamabhai 《Microbial cell factories》2010,9(1):20
Background
Mannans are one of the key polymers in hemicellulose, a major component of lignocellulose. The Mannan endo-1,4-β-mannosidase or 1,4-β- D -mannanase (EC 3.2.1.78), commonly named β-mannanase, is an enzyme that can catalyze random hydrolysis of β-1,4-mannosidic linkages in the main chain of mannans, glucomannans and galactomannans. The enzyme has found a number of applications in different industries, including food, feed, pharmaceutical, pulp/paper industries, as well as gas well stimulation and pretreatment of lignocellulosic biomass for the production of second generation biofuel. Bacillus licheniformis is a Gram-positive endospore-forming microorganism that is generally non-pathogenic and has been used extensively for large-scale industrial production of various enzymes; however, there has been no previous report on the cloning and expression of mannan endo-1,4-β-mannosidase gene (manB) from B. licheniformis. 相似文献6.
Tada R Tanioka A Iwasawa H Hatashima K Shoji Y Ishibashi K Adachi Y Yamazaki M Tsubaki K Ohno N 《Glycoconjugate journal》2008,25(9):851-861
A β-d-glucan obtained from Aureobasidium pullulans (AP-FBG) exhibits various biological activities: it exhibits antitumour and antiosteoporotic effects and prevents food allergies.
An unambiguous structural characterisation of AP-FBG is still awaited. The biological effects of β-d-glucan are known to depend on its primary structures, conformation, and molecular weight. Here, we elucidate the primary
structure of AP-FBG by NMR spectroscopy, and evaluate its biological activities. Its structure was shown to comprise a mixture
of a 1-3-β-d-glucan backbone with single 1-6-β-d-glucopyranosyl side-branching units every two residues (major structure) and a 1-3-β-d-glucan backbone with single 1-6-β-d-glucopyranosyl side-branching units every three residues (minor structure). Furthermore, this β-d-glucan exhibited immunostimulatory effects such as the accumulation of immune cells and priming effects against enterobacterium.
To our knowledge, 1-3-β-glucans like AP-FBG with such a high number of 1-6-β-glucopyranosyl side branching have a unique structure;
nevertheless, many 1-3-β-glucans were isolated from various sources, e.g. fungi, bacteria, and plants. 相似文献
7.
Elin Säwén Eine Huttunen Xue Zhang Zhennai Yang Göran Widmalm 《Journal of biomolecular NMR》2010,47(2):125-134
The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in
situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects
of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides
were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT
experiments. The EPS is composed of hexasaccharide repeating units with the following structure: → 3)[α-d-Glcp-(1 → 4)]-β-d-Galp-(1 → 4)-β-d-Glcp-(1 → 4)[β-d-Galf-(1 → 6)]-β-d-Glcp-(1 → 6)-β-d-Glcp-(1 →, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently
are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two
terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined
using translational diffusion experiments which resulted in Mw = 62 kDa, corresponding to 64 repeating units in the EPS. 相似文献
8.
Hemicellulose bioconversion 总被引:24,自引:0,他引:24
Saha BC 《Journal of industrial microbiology & biotechnology》2003,30(5):279-291
Various agricultural residues, such as corn fiber, corn stover, wheat straw, rice straw, and sugarcane bagasse, contain about
20–40% hemicellulose, the second most abundant polysaccharide in nature. The conversion of hemicellulose to fuels and chemicals
is problematic. In this paper, various pretreatment options as well as enzymatic saccharification of lignocellulosic biomass
to fermentable sugars is reviewed. Our research dealing with the pretreatment and enzymatic saccharification of corn fiber
and development of novel and improved enzymes such as endo-xylanase, β-xylosidase, and α-l-arabinofuranosidase for hemicellulose bioconversion is described. The barriers, progress, and prospects of developing an
environmentally benign bioprocess for large-scale conversion of hemicellulose to fuel ethanol, xylitol, 2,3-butanediol, and
other value-added fermentation products are highlighted. 相似文献
9.
Aspergillus tamarii produced extracellular xylanase and intracellular β-xylosidase inductively in washed glucose-grown mycelia incubated with
xylan and methyl β-d-xyloside, a synthetic glycoside. Methyl β-d-xyloside was a more effective inducer than xylan at the same concentration for both enzymes. Glucose and cycloheximide were
found to inhibit xylanase production by methyl β-d-xyloside. Methyl β-d-xyloside was hydrolyzed to xylose by mycelial extract in vitro.
Received: 23 May 1996 / Received revision: 5 September 1996 / Accepted: 13 October 1996 相似文献
10.
Membrane fractions and digitonin-solubilized enzymes prepared from stem segments isolated from the third internode of etiolated pea seedlings (Pisum sativum L. cv. Alaska) catalyzed the synthesis of a -1,4-[su14C]mannan from GDP-d-[U-14C]-mannose, a mixed -1,3- and -1,4-[14C]glucan from GDP-d-[U-14C]-glucose and a -1,4-[14C]-glucomannan from both GDP-d-[U-14C]mannose and GDP-d-[U-14C]glucose. The kinetics of the membrane-bound and soluble mannan and glucan synthases were determined. The effects of ions, chelators, inhibitors of lipid-linked saccharides, polyamines, polyols, nucleotides, nucleoside-diphosphate sugars, acetyl-CoA, group-specific chemical probes, phospholipases and detergents on the membrane-bound mannan and glucan synthases were investigated. The -glucan synthase had different properties from other preparations which bring about the synthesis of -1,3-glucans (callose) and mixed -1,3- and -1,4-glucans and which use UDP-d-glucose as substrate. It also differed from xyloglucan synthase because in the presence of several concentrations of UDP-d-xylose in addition to GDP-d-glucose no xyloglucan was formed. Using either the membrane-bound or the soluble mannan synthase, GDP-d-glucose acted competitively in the presence of GDP-d-mannose to inhibit the incorporation of mannose into the polymer. This was not due to an inhibition of the transferase activity but was a result of the incorporation of glucose residues from GDP-d-glucose into a glucomannan. The kinetics and the composition of the synthesized glucomannan depended on the ratio of the concentrations of GDP-d-glucose and GDP-d-mannose that were available. Our data indicated that a single enzyme has an active centre that can use both GDP-d-mannose and GDP-d-glucose to bring about the synthesis of the heteropolysaccharide.Abbreviations CHAPS
3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate
- CHAPSO
3-[(3-cholamidopropyl)-dimethylammonio]-2-hydroxy-1-propanesulfonate
- CHD
1,2-cyclohexanedione
- CDP
cytidine 5-diphosphate
- EGTA
ethylene glycol-bis(-aminoethyl ether) N,N,N,N-tetraacetic acid
- GDP
guanosine 5-diphosphate
- NAI
N-acetyl-imidazole
- NEM
N-ethylmaleimide
- PGO
phenylglyoxal
This work has been made possible by grants of M.A.F. and M.U.R.S.T. 40% of Italy. Dr. A. Zuppa wishes to thank the C.N.R. of Italy for his research scolarship. 相似文献
11.
Paula Alayón-Luaces Eduardo A. Pagano Luis A. Mroginski Gabriel O. Sozzi 《Plant Cell, Tissue and Organ Culture》2010,101(1):1-10
Sucrose presence and concentration modulated in different ways and to different extents the activity of six plant glycoside
hydrolases (PGHs) extracted from apple callus cultures, both in the water soluble fraction (WS-F) and in the NaCl-released
fraction (NaCl-F). β-d-Glucosidase activity increased because of sucrose starvation and the addition of sucrose decreased both WS-F and NaCl-F β-d-glucosidase from calli grown in a Murashige and Skoog’s basal medium with (MSH) or without (MS0) plant growth regulators
(PGRs). WS-F and NaCl-F α-l-arabinofuranosidase, NaCl-F β-d-galactosidase and NaCl-F β-d-xylosidase activity reached a maximum when 0.045 M sucrose was added to the MS0 medium with an ensuing decline at higher
sucrose concentrations. α-d-Galactosidase and α-d-xylosidase activity reached a maximum when 0.045 M sucrose was supplied and did not decline significantly in 0.09 M sucrose-supplied
calli. When the effects of PGR presence or absence were analysed, NaCl-F β-d-glucosidase, α-d-galactosidase, β-d-galactosidase, α-d-xylosidase and β-d-xylosidase activities were found to be higher in MS0 than in MSH. To assess whether sugar effects were sucrose-specific,
other sugars (glucose, fructose, galactose, maltose, lactose, raffinose, sorbitol and mannitol) were tested, with or without
PGR supplementation. In general, sugar alcohols (mannitol, sorbitol) and some monosaccharides (fructose and glucose in particular)
were better inducers of NaCl-F α-l-arabinofuranosidase, β-d-galactosidase and β-d-xylosidase activity than disaccharides (sucrose, maltose, and lactose) or the trisaccharide raffinose. This trend was not
widespread to all PGHs assessed since sucrose-supplemented calli displayed higher NaCl-F α-d-galactosidase than those supplemented with glucose, galactose, sorbitol or mannitol. These results show that sugars supplied
to callus tissue cultures as a carbon source can also modulate PGH activity. Modulation is different for each PGH, sugar-specific
and, at least in the case of sucrose, concentration-dependent. Results also suggest the existence of regulatory interactions
between PGRs and sugars as part of an intricate sensing and signalling network. Combination of PGR, sugar type and concentration
should be taken into account to maximize each PGH activity for further enzyme studies. 相似文献
12.
13.
Giffhorn F 《Applied microbiology and biotechnology》2000,54(6):727-740
Pyranose oxidases are widespread among lignin-degrading white rot fungi and are localized in the hyphal periplasmic space.
They are relatively large flavoproteins which oxidize a number of common monosaccharides on carbon-2 in the presence of oxygen
to yield the corresponding 2-keto sugars and hydrogen peroxide. The preferred substrate of pyranose oxidases is d-glucose which is converted to 2-keto-d-glucose. While hydrogen peroxide is a cosubstrate in ligninolytic reactions, 2-keto-d-glucose is the key intermediate of a secondary metabolic pathway leading to the antibiotic cortalcerone. The finding that
2-keto-d-glucose can serve as an intermediate in an industrial process for the conversion of d-glucose into d-fructose has stimulated research on the use of pyranose oxidases in biotechnical applications. Unique catalytic potentials
of pyranose oxidases have been discovered which make these enzymes efficient tools in carbohydrate chemistry. Converting common
sugars and sugar derivatives with pyranose oxidases provides a pool of sugar-derived intermediates for the synthesis of a
variety of rare sugars, fine chemicals and drugs.
Received: 26 April 2000 / Received revision: 8 June 2000 / Accepted: 9 June 2000 相似文献
14.
Proteins have been considered to consist exclusively of l-amino acids in living tissues. However, our previous studies showed that two specific aspartyl (Asp) residues in αA- and
αB-crystallins from human eye lenses invert to the d-isomers to a high degree during aging. The reaction is also accompanied by isomerization into a form containing β-Asp (isoaspartate)
residues. The appearance of d- and β-Asp in a protein potentially induces large changes to the higher order structure of the protein as well as to its
function. However, it remains unclear whether the formation of the Asp isomer is the direct trigger of the change to the higher
order structure and function. In this study, in order to clarify the effect of the inversion to d-isomers in a protein, we synthesized peptides corresponding to the 70–88 (KFVIFLDVKHFSPEDLTVK) fragment of human αA-crystallin
and its corresponding diastereoisomers in which lα-Asp was replaced with lβ-Asp, dα-Asp, and dβ-Asp at position 76 and compared their biochemical properties with that of normal peptide. The peptides containing abnormal
isomers (lβ-Asp, dα-Asp, and dβ-Asp residues, respectively) were more hydrophilic than the normal peptide (containing lα-Asp), lost β-sheet structure and changed to random structures. The normal peptide promoted the aggregation of insulin while
the other three isomers suppressed the aggregation of insulin. This is the first evidence that a single substitution of an
Asp isomer in a peptide induces a large change to the properties of the peptide. 相似文献
15.
Selection of a large number of different strains of hyphal fungi of the genusAspergillus, capable of production of extracellular mannosidase and mannanase type enzymes, was carried out. Before cultivating the strains
on liquid synthetic medium containing 0.5%Saccharomyces cerevisiae mannan as the carbon source, they were adapted by multiple passage on solid synthetic media containingd-mannose,d-mannose and α-mannan and lastly only α-mannan. The extracellular enzymatic preparations of the mould fungi were tested for
their ability to hydrolyse three different substrates—Saccharomyces cerevisiae, Torulopsis ingeniosa andTorulopsis colliculosa mannan. The production of α-mannosidase was found to be specifically dependent on the character of the substrate used for
cultivation of the fungus. 相似文献
16.
A novel phosphorylase from Clostridium phytofermentans belonging to the glycoside hydrolase family (GH) 65 (Cphy1874) was characterized. The recombinant Cphy1874 protein produced
in Escherichia coli showed phosphorolytic activity on nigerose in the presence of inorganic phosphate, resulting in the release of d-glucose and β-d-glucose 1-phosphate (β-G1P) with the inversion of the anomeric configuration. Kinetic parameters of the phosphorolytic activity
on nigerose were k
cat = 67 s−1 and K
m = 1.7 mM. This enzyme did not phosphorolyze substrates for the typical GH65 enzymes such as trehalose, maltose, and trehalose
6-phosphate except for a weak phosphorolytic activity on kojibiose. It showed the highest reverse phosphorolytic activity
in the reverse reaction using d-glucose as the acceptor and β-G1P as the donor, and the product was mostly nigerose at the early stage of the reaction. The
enzyme also showed reverse phosphorolytic activity, in a decreasing order, on d-xylose, 1,5-anhydro-d-glucitol, d-galactose, and methyl-α-d-glucoside. All major products were α-1,3-glucosyl disaccharides, although the reaction with d-xylose and methyl-α-d-glucoside produced significant amounts of α-1,2-glucosides as by-products. We propose 3-α-d-glucosyl-d-glucose:phosphate β-d-glucosyltransferase as the systematic name and nigerose phosphorylase as the short name for this Cphy1874 protein. 相似文献
17.
Nielsen KA Hrmova M Nielsen JN Forslund K Ebert S Olsen CE Fincher GB Møller BL 《Planta》2006,223(5):1010-1023
Barley (Hordeum vulgare L.) produces a leucine-derived cyanogenic β-d-glucoside, epiheterodendrin that accumulates specifically in leaf epidermis. Barley leaves are not cyanogenic, i.e. they
do not possess the ability to release hydrogen cyanide, because they lack a cyanide releasing β-d-glucosidase. Cyanogenesis was reconstituted in barley leaf epidermal cells through single cell expression of a cDNA encoding
dhurrinase-2, a cyanogenic β-d-glucosidase from sorghum. This resulted in a 35–60% reduction in colonization rate by an obligate parasite Blumeria graminis f. sp. hordei, the causal agent of barley powdery mildew. A database search for barley homologues of dhurrinase-2 identified
a (1,4)-β-d-glucan exohydrolase isozyme βII that is located in the starchy endosperm of barley grain. The purified barley (1,4)-β-d-glucan exohydrolase isozyme βII was found to hydrolyze the cyanogenic β-d-glucosides, epiheterodendrin and dhurrin. Molecular modelling of its active site based on the crystal structure of linamarase
from white clover, demonstrated that the disposition of the catalytic active amino acid residues was structurally conserved.
Epiheterodendrin stimulated appressoria and appressorial hook formation of B. graminis in vitro, suggesting that loss of cyanogenesis in barley leaves has enabled the fungus to utilize the presence of epiheterodendrin
to facilitate host recognition and to establish infection. 相似文献
18.
Xylan 1,4-β-D-xylosidase catalyzes hydrolysis of non-reducing end xylose residues from xylooligosaccharides. The enzyme is
currently used in combination with β-xylanases in several large-scale processes for improving baking properties of bread dough,
improving digestibility of animal feed, production of d-xylose for xylitol manufacture, and deinking of recycled paper. On a grander scale, the enzyme could find employment alongside
cellulases and other hemicellulases in hydrolyzing lignocellulosic biomass so that reaction product monosaccharides can be
fermented to biofuels such as ethanol and butanol. Catalytically efficient enzyme, performing under saccharification reactor
conditions, is critical to the feasibility of enzymatic saccharification processes. This is particularly important for β-xylosidase
which would catalyze breakage of more glycosidic bonds of hemicellulose than any other hemicellulase. In this paper, we review
applications and properties of the enzyme with emphasis on the catalytically efficient β-d-xylosidase from Selenomonas ruminantium and its potential use in saccharification of lignocellulosic biomass for producing biofuels. 相似文献
19.
Lipomyces starkeyi is an oleaginous yeast, and has been classified in four distinct groups, i.e., sensu stricto and custers α, β, and γ. Recently,
L. starkeyi clusters α, β, and γ were recognized independent species, Lipomyces mesembrius, Lipomyces doorenjongii, and Lipomyces kockii, respectively. In this study, we investigated phylogenetic relationships within L. starkeyi, including 18 Japanese wild strains, and its related species, based on internal transcribed spacer sequences and evaluated
biochemical characters which reflected the phylogenetic tree. Phylogenetic analysis showed that most of Japanese wild strains
formed one clade and this clade is more closely related to L. starkeyi s.s. clade including one Japanese wild strain than other clades. Only three Japanese wild strains were genetically distinct
from L. starkeyi. Lipomyces mesembrius and L. doorenjongii shared one clade, while L. kockii was genetically distinct from the other three species. Strains in L. starkeyi s.s. clade converted six sugars, d-glucose, d-xylose, l-arabinose, d-galactose, d-mannose, and d-cellobiose to produce high total lipid yields. The Japanese wild strains in subclades B, C, and D converted d-glucose, d-galactose, and d-mannose to produce high total lipid yields. Lipomyces mesembrius was divided into two subclades. Lipomyces mesembrius CBS 7737 converted d-xylose, l-arabinose, d-galactose, and d-cellobiose, while the other L. mesembrius strains did not. Lipomyces doorenjongii converted all the sugars except d-cellobiose. In comparison to L. starkeyi, L. mesembrius, and L. doorenjongii, L. kockii produced higher total lipid yields from d-glucose, d-galactose, and d-mannose. The type of sugar converted depended on the subclade classification elucidated in this study. 相似文献
20.
Production of β-Mannanase and β-Mannosidase from Aspergillus awamori K4 and Their Properties 总被引:6,自引:0,他引:6
β-Mannanase and β-mannosidase from Aspergillus awamori K4 was produced by solid culture with coffee waste and wheat bran. The optimum composition for enzyme production was 40%
coffee waste–60% wheat bran. Two enzymes were partially purified. Optimum pH was about 5 for both enzymes, and optimum temperature
was around 80°C for β-mannanase and 60–70°C for β-mannosidase. These enzymes produced some oligosaccharides from glucomannan
and galactomannan by their hydrolyzing and transferring activities. β-Mannanase hydrolyzed konjak and locust bean gum 39.1%
and 15.8%, respectively. Oligosaccharides of various molecular size were released from glucomannan of konjak, but on the addition
of cellulase, mannobiose was released selectively. In locust bean gum, tetra-, tri-, and disaccharides (mannobiose) were mainly
released by K4 β-mannanase. Tetra- and trisaccharides were heterooligosaccharides consisting of galactose and mannose residues.
K4 β-mannosidase had a transglycosylation action, transferring mannose residue to alcohols and sugars like fructose.
Received: 24 April 2000/Accepted: 20 October 2000 相似文献