Abstract：
:The hydrolytic activity of a thermophilic cyclomaltodextrinase (CMD) from Anoxybacillus flavithermus ZNU-NGA and a representative single mutant were investigated against soluble substrates including α-, β- and γ-cyclomaltodestrines (CDs). Based on the occurrence of arginine (Arg) at position 403 in some homologue proteins, His403 in Wild-type (WT) CMD was replaced with Arg (H403R variant) with site-directed mutagenesis procedures. According to bioinformatics data, Arg403 in mutant protein is located near Glu357 as one of the catalytic residues in a manner that they are able to create a medium-range attractive electrostatistic interaction. Structural studies by Far UV-CD showed that this mutation is accompanied by conversion of a small fraction of α-helix to β-form structure. Fluorescence data reveals that, the hydrophobic regions at the surface of protein, as the binding sites for ANS (8-Anilinonaphthalene-1-sulfonic acid) increase in mutant protein, demonstrating relative inflation of H403R variant compared with WT protein. However, the polarity of microenvironment around chromophores did not change upon mutation. Activity measurement in different ranges of pH and temperatures showed that the optimum values of pH and temperature in mutant enzyme is the same as WT enzyme, however; the activity at optimum points increased in H403R variant. It was also revealed that the H403R variant had slightly improved catalytic efficiency for γ-CD. The same value of activation parameters for both protein variants indicates that mutation does not alter the mechanism of catalysis during enzyme-substrate formation.
journal_name
Enzyme Microb Technoljournal_title
Enzyme and microbial technologyauthors
Mirzaee Z,Jafarian V,Shirdel SA,Khalifeh Kdoi
10.1016/j.enzmictec.2019.109421subject
Has Abstractpub_date
2019-12-01 00:00:00pages
109421eissn
0141-0229issn
1879-0909pii
S0141-0229(19)30159-0journal_volume
131pub_type
杂志文章abstract：:Amoxicillin can be produced in an enzymatic suspension-to-suspension reaction in which the substrate(s) and product(s) are mainly present as solid particles, while the reaction takes place in the liquid phase. During these suspension-to-suspension reactions different subprocesses take place, such as dissolution/crysta...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/s0141-0229(00)00245-3
更新日期：2000-11-01 00:00:00
abstract：:This study examined the potential of untreated and alkali-pretreated sugarcane bagasse (SCB) in cellulase, reducing sugar (RS) and fungal biomass production via solid state fermentation (SSF) using Pycnoporus sanguineus. The impact of the composition, structure and cellulase adsorption ability of SCB on the production...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2013.05.005
更新日期：2013-09-10 00:00:00
abstract：:Astragalin (kaempferol-3-O-β-D-glucopyranoside, Ast) glucosides were synthesized by the acceptor reaction of a dextransucrase produced by Leuconostoc mesenteroides B-512FMCM with astragalin and sucrose. Each glucoside was purified and their structures were assigned as kaempferol-3-O-β-D-glucopyranosyl-(1→3)-O-α-D-gluc...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2011.09.007
更新日期：2012-01-05 00:00:00
abstract：:Malolactic fermentation (MLF) is a secondary bioconversion developed in some wines involving malic acid decarboxylation. The induction of MLF in wine by cultures of free and immobilized Oenococcus oeni cells was investigated. This work reports on the effect of surface charges in the immobilization material, a recently...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/s0141-0229(00)00339-2
更新日期：2001-03-08 00:00:00
abstract：:Crocin, one of the major carotenoid pigments of Crocus sativus (saffron), is responsible for antioxidant activity, neuroprotection, and the inhibition of tumor cell proliferation. In order to improve the functionality of crocin, α-glucosyl-(1→6)-trans-crocins (C-Gs) were synthesized using sucrose and dextransucrase fr...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2020.109630
更新日期：2020-10-01 00:00:00
abstract：:Nitrification kinetics of synthetic saline wastewater was investigated by using an activated sludge unit. Initial experiments were performed with salt-free wastewater to obtain baseline information. Experiments with 3% salt concentration were performed at different sludge ages in order to investigate the system perfor...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/s0141-0229(01)00312-x
更新日期：2001-05-07 00:00:00
abstract：:Different whole-cell immobilization methods and conditions were tested for the delta 1-dehydrogenation of 6-alpha-methyl-hydrocortisone-21-acetate with Arthrobacter simplex cells, in n-decane-1-ol and chloroform. Among the entrapment methods, polyurethane foams gave the best productivity of n-decane-1-ol, but could no...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(92)90036-n
更新日期：1992-08-01 00:00:00
abstract：:Continuous culture and fed-batch fermentations were used to test the behavior of the system Bacillus subtilis DN1885(pCH7) that synthesizes a recombinant beta-1,4-endoglucanase. Continuous culture experiments were focused on the study of the instability aspects of the system as well as determination of the biomass gro...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/s0141-0229(00)00203-9
更新日期：2000-08-01 00:00:00
abstract：:This study aimed to improve the thermostability of a newly cloned tyrosinase from Streptomyces kathirae SC-1. The POPMuSiC algorithm was applied to predict the folding free energy change (ΔDG) of amino acid substitution. Site-directed mutagenesis was used to construct mutants (Q7K, G234P, and Q7K/G234P), and the mutan...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2015.06.002
更新日期：2015-09-01 00:00:00
abstract：:The selected thermotolerant, lactose-utilizing yeast strain Kluyveromyces marxianus NBIMCC 8362 possesses high specific d-amino acid oxidase activity (60Ug(-1)), which was increased nine-fold (545Ug(-1)) by design of the growth medium and conditions for d-amino oxidase induction. Applying an optimized simple and rapid...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2007.08.010
更新日期：2008-01-01 00:00:00
abstract：:6-(N-hydroxyethyl)-amino-6-deoxy-l-sorbofuranose (6NSL), a key precursor in the synthesis of miglitol, is produced from N-2-hydroxyethyl-glucamine (NHEG) by the regioselective oxidation of Gluconobacter oxydans. The limitation of PQQ biosynthesis became a bottleneck for improvement of PQQ-dependent D-sorbitol dehydrog...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2020.109670
更新日期：2020-11-01 00:00:00
abstract：:A method is described for construction of a highly sensitive electrochemical biosensor for detection of glutamate. The biosensor is based on covalent immobilization of glutamate oxidase (GluOx) onto polypyrrole nanoparticles and polyaniline composite film (PPyNPs/PANI) electrodeposited onto Au electrode. The enzyme el...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.02.001
更新日期：2014-04-10 00:00:00
abstract：:Advantages in maltose fermentation at extremely low temperatures (5-10°C) using an alcohol resistant and cryotolerant yeast strain (Saccharomyces cerevisiae AXAZ-1) immobilized on porous cellulosic material (or tubular cellulose, TC), produced by delignification of wood sawdust, are reported. Pure maltose and glucose ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.08.007
更新日期：2014-11-01 00:00:00
abstract：:In this study, we report the enzymatic production of glycerol acetate from glycerol and methyl acetate. Lipases are essential for the catalysis of this reaction. To find the optimum conditions for glycerol acetate production, sequential experiments were designed. Type of lipase, lipase concentration, molar ratio of re...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.11.004
更新日期：2015-02-01 00:00:00
abstract：:Even though many enzyme processes occur at the interface of an insoluble substrate, these reactions are generally much less studied than homogenous enzyme reactions in the aqueous bulk. Interfacial (or heterogeneous) enzyme reactions involve several reaction steps, and the established experimental approach to elucidat...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2017.06.009
更新日期：2017-10-01 00:00:00
abstract：:A straightforward synthesis of gold nanoparticles (AuNps) is achieved by novel probiotic Lactobacillus kimchicus DCY51T isolated from Korean kimchi via an intracellular membrane-bound mechanism. The bioreduction of HAuCl4 into AuNps was verified by ultraviolet-visible spectrophotometry at ∼540nm. AuNps were spherical ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2016.08.018
更新日期：2016-12-01 00:00:00
abstract：:An extracellular esterase from the actinomycetes Amycolatopsis orientalis was found by screening. It is capable of splitting the isomeric mixture (K/J) of (I, Scheme 1) into 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid, pivalic acid, and acetaldehyde with a high yield. The purified enzyme of 55.4 Kd by SDS-PAGE ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(95)00171-9
更新日期：1996-07-01 00:00:00
abstract：:A method to stably immobilize microbes on electrodes was developed. Resting cells of Methylobacterium extorquens AM1(MeAM1) were caged within multiwalled carbon nanotubes (MWNTs)by adding the cells to a water dispersion of MWNTs then allowing the resulting mixture to dry on electrodes. The MeAM1-MWCNTs electrode thus ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2018.06.004
更新日期：2018-10-01 00:00:00
abstract：:We here describe a unique β-D-glucosidase (BGL; Blon_0625) derived from Bifidobacterium longum subsp. infantis ATCC 15697. The Blon_0625 gene was expressed by recombinant Escherichia coli. Purified recombinant Blon_0625 retains hydrolyzing activity against both p-nitrophenyl-β-D-glucopyranoside (pNPG; 17.3±0.24Umg(-1)...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.10.001
更新日期：2015-01-01 00:00:00
abstract：:Different lipases have been immobilized on octyl agarose beads at 1mg/g and at maximum loading, via physical interfacial activation versus the octyl layer on the support. The stability of the preparations was analyzed. Most biocatalysts had the expected result: the apparent stability increased using the highly loaded ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2016.12.002
更新日期：2017-03-01 00:00:00
abstract：:The effect of treatment with various intercalating dyes on the ability to produce antibiotics in Micromonospora rosaria and Micromonospora purpurea was studied. Treatment with acriflavine resulted in a high frequency loss of antibiotic productivity in both species. In M. rosaria, the loss of antibiotic-producing abili...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(90)90128-d
更新日期：1990-08-01 00:00:00
abstract：:Based on a differential pre-screening of 44 white-rot fungi on a lignocellulose-supplemented minimal medium, four basidiomycetes were selected for further study: Ganoderma lucidum, Polyporus brumalis, Polyporus ciliatus and Trametes versicolor. Only G. lucidum was able to grow vividly on malt extract or minimal media ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2013.08.003
更新日期：2013-12-10 00:00:00
abstract：:NADPH is the key cofactor in L-isoleucine (Ile) biosynthetic pathway. To increase the Ile biosynthesis in Corynebacterium glutamicum ssp. lactofermentum JHI3-156, NADPH supply needs to be enhanced. Here NAD kinase, the key enzyme for the de novo biosynthesis of NADP(+) and NADPH, were cloned and expressed in JHI3-156,...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2012.04.003
更新日期：2012-07-15 00:00:00
abstract：:The methyl ester of 2-benzoxazolon-3-yl-acetic acid was used as an acyl donor in the penicillin amidase-catalysed transfer reaction to 7-aminodesacetoxycephalosporanic acid. The synthesis of 7-(2-benzoxazolon-3-yl-acetamido)-desacetoxycephalosporanic acid was carried out as a kinetically controlled reaction. A charact...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(92)90144-d
更新日期：1992-06-01 00:00:00
abstract：:The fatty acid methyl esters and fatty acid ethyl esters are known as biodiesels which are considered to be renewable, nontoxic and biodegradable biofuels. However, the conventional biodiesels show a high crystallization temperature which is one of the most critical obstacles against the widespread biodiesel usage. Th...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2017.03.012
更新日期：2017-07-01 00:00:00
abstract：:We generated a bifunctional enzyme chimera containing the xylanase and lichenase coupled with SpyTag between them. Meanwhile, we generated another chimera containing SpyCatcher and elastin-like polypeptides (ELPs). As ELPs could bond to the xylanase-lichenase chimera through SpyTag/SpyCatcher spontaneous reaction in m...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2018.04.007
更新日期：2018-08-01 00:00:00
abstract：:Hydrolysis of lignocellulosic biomass depends on the concerted actions of cellulases and accessory proteins. In this work we examined the combined action of two auxiliary proteins from the brown rot fungus Gloeophyllum trabeum: a family AA9 lytic polysaccharide monooxygenase (GtLPMO) and a GH10 xylanase (GtXyn10A). Th...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2017.11.007
更新日期：2018-06-01 00:00:00
abstract：:A reactive water-soluble polymer was synthesized by copolymerizing N-isopropylacrylamide and glycidyl acrylate. The reactive polymer could react with the amino groups of enzymes/proteins or other ligands to form an affinity polymer. As a model, the reactive polymer was allowed to react with paraaminobenzamidine, a str...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(90)90005-b
更新日期：1990-09-01 00:00:00
abstract：:In this work, porous biochar derived from sugarcane bagasse was prepared and then coated with different amounts of chitosan (C@CS) for cellulase immobilization. Cellulase was covalently immobilized on the support by using glutaraldehyde as a linker. The chemical characteristics and morphology of the samples were deter...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2020.109561
更新日期：2020-08-01 00:00:00
abstract：:Phytate is the major storage form of phosphorus in plants. It is present in cereals and raw materials of vegetable origin used in animal and human diets. However, non-ruminant animals have little phytase activity in their guts and, therefore, cannot digest phytate. As a result, almost all dietary phytate is discharged...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2020.109533
更新日期：2020-06-01 00:00:00
