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1.
Cloning and sequence analysis of a novel xylanase gene, Auxyn10A, from Aspergillus usamii 总被引:1,自引:0,他引:1
A full-length cDNA sequence, encoding a novel endo-1,4-β-d-xylanase (AuXyn10A) of Aspergillus usamii, was obtained by using rapid amplification of cDNA ends (RACE) methods and cloned into the pUCm-T vector, followed by DNA
sequencing. The cDNA gene, designated as Auxyn10A, is 1,235 bp in length harboring 5′- and 3′-non-encoding regions, as well as an ORF of 984 bp that encodes a 19-aa signal
peptide, a 6-aa propeptide and a 302-aa mature peptide with a calculated MW of 32,756 Da. The AuXyn10A displays high similarity
to the xylanases of Aspergillus niger, Aspergillus kawachii and Aspergillus niger, members of the glycoside hydrolase family 10. Its three-dimensional structure was predicted using programs based on the crystal structure of Penicillium simplicissimum xylanase (1B30_A) from the family 10. The complete DNA gene was cloned from the genomic DNA of A. usamii using conventional PCR and hairpin structure-mediated PCR techniques. The DNA gene is 2,255 bp in length, containing a 510 bp
of 5′-flanking promoter region and a 1,745 bp of downstream fragment that consists of ten exons and nine short introns ranging
from 52 to 62 bp. 相似文献
2.
Huiying Luo Jun Yang Jiang Li Pengjun Shi Huoqing Huang Yingguo Bai Yunliu Fan Bin Yao 《Applied microbiology and biotechnology》2010,86(6):1829-1839
We cloned and sequenced a xylanase gene named xylD from the acidophilic fungus Bispora sp. MEY-1 and expressed the gene in Pichia pastoris. The 1,422-bp full-length complementary DNA fragment encoded a 457-amino acid xylanase with a calculated molecular mass of
49.8 kDa. The mature protein of XYLD showed high sequence similarity to both glycosyl hydrolase (GH) families 5 and 30 but
was more homologous to members of GH 30 based on phylogenetic analysis. XYLD shared the highest identity (49.9%) with a putative
endo-1,6-β-d-glucanase from Talaromyces stipitatus and exhibited 21.1% identity and 34.3% similarity to the well-characterized GH family 5 xylanase from Erwinia chrysanthemi. Purified recombinant XYLD showed maximal activity at pH 3.0 and 60 °C, maintained more than 60% of maximal activity when
assayed at pH 1.5–4.0, and had good thermal stability at 60 °C and remained stable at pH 1.0–6.0. The enzyme activity was
enhanced in the presence of Ni2+ and β-mercaptoethanol and inhibited by some metal irons (Hg2+, Cu2+, Pb2+, Mn2+, Li+, and Fe3+) and sodium dodecyl sulfate. The specific activity of XYLD for beechwood xylan, birchwood xylan, 4-O-methyl-d-glucuronoxylan, and oat spelt xylan was 2,463, 2,144, 2,020, and 1,429 U mg−1, respectively. The apparent K
m and V
max values for beechwood xylan were 5.6 mg ml−1 and 3,622 μmol min−1 mg−1, respectively. The hydrolysis products of different xylans were mainly xylose and xylobiose. 相似文献
3.
A recombinant putative β-galactosidase from Thermoplasma acidophilum was purified as a single 57 kDa band of 82 U mg−1. The molecular mass of the native enzyme was 114 kDa as a dimer. Maximum activity was observed at pH 6.0 and 90°C. The enzyme
was unstable below pH 6.0: at pH 6 its half-life at 75°C was 28 days but at pH 4.5 was only 13 h. Catalytic efficiencies decreased
as p-nitrophenyl(pNP)-β-d-fucopyranoside (1067) > pNP-β-d-glucopyranoside (381) > pNP-β-d-galactopyranoside (18) > pNP-β-d-mannopyranoside (11 s−1 mM−1), indicating that the enzyme was a β-glycosidase. 相似文献
4.
Characterization of a cell wall invertase gene TaCwi-A1 on common wheat chromosome 2A and development of functional markers 总被引:2,自引:0,他引:2
Dongyun Ma Jun Yan Zhonghu He Ling Wu Xianchun Xia 《Molecular breeding : new strategies in plant improvement》2012,29(1):43-52
Cell wall invertase (CWI) is a critical enzyme for sink tissue development and carbon partition, and has a high association
with kernel weight. Characterization of Cwi genes and development of functional markers are of importance for marker-assisted selection in wheat breeding. In the present
study, the full-length genomic DNA sequence of a Cwi gene located on wheat chromosome 2A, designated TaCwi-A1, was characterized by in silico cloning and experimental validation. TaCwi-A1 comprises seven exons and six introns, with 3,676 bp in total, and an open reading frame (ORF) of 1,767 bp. A pair of complementary
dominant markers, CWI21 and CWI22, was developed based on allelic variations at the TaCwi-A1 locus. A 404-bp PCR fragment was amplified by CWI21 in varieties with lower kernel weights, whereas a 402-bp fragment was
generated by CWI22 in the varieties with higher kernel weights. The markers CWI21 and CWI22 were located on chromosome 2AL
using a F2:3 population from a cross Doumai/Shi 4185, and a set of Chinese Spring nullisomic–tetrasomic lines. They were linked to the
SSR locus Xbarc15-2AL with a genetic distance of 10.9 cM. QTL analysis indicated that TaCwi-A1 could explain 4.8% of phenotypic variance for kernel weight over 2 years. Two sets of Chinese landraces and two sets of commercial
wheat varieties were used to validate the association of CWI21 and CWI22 with kernel weight. The results indicated that the
functional markers CWI21 and CWI22 were closely related to kernel weight and could be used in wheat breeding for improving
grain yield. 相似文献
5.
Consensus amino acid sequences of FADH2-dependent bacterial halogenases were used to design PCR primers amplifying a halogenase gene fragment from the chloramphenicol
producer Streptomyces venezuelae ISP5230. The sequence-specific degenerate primers (MPF1 and MPR2) were used with a touchdown PCR procedure in the first PCR-assisted
cloning of a halogenase gene fragment. In the region of the 290-bp PCR product containing the reverse primer, the deduced
amino acid sequence exhibited characteristics of a β–α–β fold present in FAD-binding sites of certain monooxygenases. When
used to probe Southern blots of restriction-enzyme-digested DNA, the [α-32P]dCTP-labeled PCR product hybridized specifically with DNA fragments from genomic DNA of S. venezuelae ISP5230. Primers MPF1 and MPR2 also allowed amplification by PCR of approximately 290-bp DNA fragments from several other
streptomycetes. The fragments from Streptomyces aureofaciens NRRL2209 and Streptomyces coelicolor A3(2) showed sequence identity with halogenase genes from these species. Thus, the PCR primers are of potential value for
amplification and subsequent isolation of actinomycete halogenase genes. Journal of Industrial Microbiology & Biotechnology (2002) 29, 1–5 doi:10.1038/sj.jim.7000263
Received 25 June 2001/ Accepted in revised form 02 April 2002 相似文献
6.
Hsiang-Ling Chen Chen-Tien Chang Long-Liu Lin Tein-Yu Li Huei-Fen Lo 《World journal of microbiology & biotechnology》2009,25(2):323-330
To express Escherichia coli novablue dipeptidyl carboxypeptidase (EcDCP), the gene was amplified by PCR and cloned into the expression plasmid pQE-31 to yield pQE-EcDCP. His6-tagged EcDCP (His6-EcDCP) was over-expressed in E. coli M15 (pQE-EcDCP) as a soluble and active form under 0.05 mM IPTG induction at 26°C for 12 h. The recombinant enzyme was purified to homogeneity
by Ni2+-NTA resin and had a molecular mass of approximately 75 kDa. The temperature and pH optima for His6-EcDCP were 37°C and 7.0, respectively. In the presence of 200 mM NaCl, His6-EcDCP was stimulated by 1.5 fold. The K
M and k
cat values of the enzyme for N-benzoyl-l-glycyl-l-histidyl-l-leucine were 1.83 mM and 168.3 s−1, respectively. His6-EcDCP activity was dramatically inhibited by 10 mM EDTA, 0.25 mM 1.10-phenanthroline, and 2.5 mM DEPC, but it was not affected
by Ser, Asp, Lys, and Trp protease inhibitors. Analysis of His6-EcDCP by circular dichroism revealed that the secondary structures of the enzyme in 30 mM universal buffer (pH 7.0) were 17%
α-helix, 35% β-sheet and 47% random coil. Mid point of thermal transition was calculated to be 55°C for the recombinant enzyme. 相似文献
7.
Dwarf bunt of wheat, caused by Tilletia controversa Kühn, is a destructive disease on wheat as well as an important internationally quarantined disease in many countries. The primer
ISSR818 generated a polymorphic pattern displaying a 867-bp DNA fragment specific for T. controversa. The marker was converted into a sequence characterized amplified region (SCAR), and specific primers (TCKSF3/TCKSR3) designed
for use in PCR detection assays; they amplified a unique DNA fragment in all isolates of T. controversa but not in the related pathogens. The detection limit with the primer set (TCKSF3/TCKSR3) was 5 ng of DNA which could be
obtained from 5.5 μg of teliospores in a 25-μL PCR reaction mixture. 相似文献
8.
Aneta Monika Białkowska Hubert Cieśliński Karolina Maria Nowakowska Józef Kur Marianna Turkiewicz 《Archives of microbiology》2009,191(11):825-835
A psychrotrophic bacterium producing a cold-adapted β-galactosidase upon growth at low temperatures was classified as Arthrobacter sp. 20B. A genomic DNA library of strain 20B introduced into Escherichia coli TOP10F′ and screening on X-Gal (5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside)-containing agar plates led to the isolation of β-galactosidase gene. The β-galactosidase gene (bgaS) encoding a protein of 1,053 amino acids, with a calculated molecular mass of 113,695 kDa. Analysis of the amino acid sequence
of BgaS protein, deduced from the bgaS ORF, suggested that it is a member of the glycosyl hydrolase family 2. A native cold-adapted β-galactosidase was purified
to homogeneity and characterized. It is a homotetrameric enzyme, each subunit being approximately 116 kDa polypeptide as deduced
from native and SDS–PAGE, respectively. The β-galactosidase was optimally active at pH 6.0–8.0 and 25°C. P-nitrophenyl-β-d-galactopyranoside (PNPG) is its preferred substrate (three times higher activity than for ONPG—o-nitrophenyl-β-d-galactopyranoside). The Arthrobacter sp. 20B β-galactosidase is activated by thiol compounds (53% rise in activity in the presence of 10 mM 2-mercaptoethanol),
some metal ions (activity increased by 50% for Na+, K+ and by 11% for Mn2+) and inactivated by pCMB (4-chloro-mercuribenzoic acid) and heavy metal ions (Pb2+, Zn2+, Cu2+). 相似文献
9.
Chulhong Oh Chamilani Nikapitiya Youngdeuk Lee Ilson Whang Se-Jae Kim Do-Hyung Kang Jehee Lee 《Journal of industrial microbiology & biotechnology》2010,37(5):483-494
A gene (agrP) encoding a β-agarase from Pseudoalteromonas sp. AG4 was cloned and expressed in Escherichia coli. The agrP primary structure consists of an 870-bp open reading frame (ORF) encoding 290 amino acids (aa). The predicted molecular
mass and isoelectric point were determined at 33 kDa and 5.9, respectively. The signal peptide was predicted to be 21 aa.
The deduced aa sequence showed 98.6% identity to β-agarase from Pseudoalteromonas atlantica. The recombinant protein was purified as a fusion protein and biochemically characterized. The purified β-agarase (AgaP)
had specific activity of 204.4 and 207.5 units/mg towards agar and agarose, respectively. The enzyme showed maximum activity
at 55°C and pH 5.5. It was stable at pH 4.5 to 8.0 and below 55°C for 1 h. The enzyme produced neoagarohexaose and neoagarotetraose
from agar and in addition to that neoagarobiose from the agarose. The neoagarooligosaccharides were biologically active. Hence,
AgaP is a useful enzyme source for use by cosmetic and pharmaceutical industries. 相似文献
10.
Patcharaporn Siwayaprahm Mongkon Audtho Kunio Ohmiya Chanpen Wiwat 《World journal of microbiology & biotechnology》2006,22(4):331-335
Summary A DNA fragment encoding for 598 amino acids of chitinase protein from Bacillus circulans No. 4.1 was subcloned into pQE-30 expression vector and transformed into Escherichia coli M15 (pREP4). The molecular weight of the expressed protein was approximately 66 kDa. Enzymatic activity of the recombinant
protein was assayed after purification using affinity chromatography on a nickel chelating resin. The enzyme hydrolyzed N-acetylchitooligosaccharides mainly to N-acetylchitobiose, and was active toward chitin, carboxymethyl-chitin, colloidal chitin, glycol chitin and 4-methylumbelliferyl-β-d-N, N′-diacetylchitobiose. The pH and temperature optima of the chitinase enzyme were 7.0 and 45 °C, respectively. This enzyme
was stable in the pH range of 5.0–9.0 and at temperatures up to 50 °C. In addition, when cleaved by a proteolytic enzyme,
the 20-kDa product could retain high chitinolytic activity. 相似文献
11.
Koseki T Mese Y Nishibori N Masaki K Fujii T Handa T Yamane Y Shiono Y Murayama T Iefuji H 《Applied microbiology and biotechnology》2008,80(6):1007-1013
An α-l-rhamnosidase was purified by fractionating a culture filtrate of Aspergillus kawachii grown on l-rhamnose as the sole carbon source. The α-l-rhamnosidase had a molecular mass of 90 kDa and a high degree of N-glycosylation of approximately 22%. The enzyme exhibited optimal activity at pH 4.0 and temperature of 50 °C. Further, it
was observed to be thermostable, and it retained more than 80% of its original activity following incubation at 60 °C for
1 h. Its T
50 value was determined to be 72 °C. The enzyme was able to hydrolyze α-1,2- and α-1,6-glycosidic bonds. The specific activity
of the enzyme was higher toward naringin than toward hesperidin. The A. kawachii α-l-rhamnosidase-encoding gene (Ak-rhaA) codes for a 655-amino-acid protein. Based on the amino acid sequence deduced from the cDNA, the protein possessed 13 potential
N-glycosylation recognition sites and exhibited a high degree of sequence identity (up to 75%) with the α-l-rhamnosidases belonging to the glycoside hydrolase family 78 from Aspergillus aculeatus and with hypothetical Aspergillus oryzae and Aspergillus fumigatus proteins.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Recombinant plasmids encoding 3-deoxy-d-manno-oct-2-ulosonate-8-phosphate (Kdo-8-P) synthase (KdsA; EC 4.1.2.16) were identified from a cDNA library of Pisum sativum L. (pea) by complementing a temperature-sensitive kdsA
ts
mutant of the Gram-negative bacterium Salmonella enterica. Sequence analysis of several inserts revealed a central open reading frame encoding a protein of 290 amino acids with a
high degree of amino acid sequence similarity to bacterial KdsA. The cDNA was confirmed by amplifying a 1,812-bp DNA fragment
from the chromosome of pea that encoded four exons around the 5′-end of kdsA. The recombinant enzyme was subcloned, overexpressed and characterized to synthesize Kdo-8-P from d-arabinose-5-phosphate and phosphoenolpyruvate. The pH optimum was 6.1 and the activity of the enzyme was neither stimulated by the addition of divalent cations
nor inhibited by EDTA. The cDNA of kdsA could not complement Escherichia coli K-12 strain AB3257, which is defective in all three isoenzymes (AroFGH) of 3-deoxy-d-arabino-hept-2-ulosonate-7-phosphate (Dha-7-P) synthase (EC 4.1.2.15), and neither d-erythrose-4-phosphate nor d-ribose-5-phosphate could substitute for d-arabinose-5-phosphate in vitro. Thus, plant cells possess a specific enzyme for the biosynthesis of Kdo-8-P with remarkable structural and functional similarities to bacterial KdsA proteins.
Received: 14 July 2000 / Accepted: 30 August 2000 相似文献
13.
Diastereoselectivity-enhanced mutants of l-threonine aldolase (l-TA) for l-threo-3,4-dihydroxyphenylserine (l-threo-DOPS) synthesis were isolated by error-prone PCR followed by a high-throughput screening. The most improved mutant was achieved
from the mutant T3-3mm2, showing a 4-fold increase over the wild-type l-TA. When aldol condensation activity was examined using whole cells of T3-3mm2, its de was constantly maintained at 55% during
the batch reactions for 80 h, yielding 3.8 mg l-threo-DOPS/ml. 相似文献
14.
A 111-bp DNA fragment related to nikkomycin biosynthesis of Streptomyces ansochromogenes 7100 was obtained with the method of reverse genetics. Then, a 2.2-kb DNA fragment was cloned from the DNA library of S. ansochromogenes 7100 by using the 111-bp fragment as a probe. Sequence analysis showed that the fragment contains one complete open reading
frame (ORF) that encodes a 219-amino acid (aa) protein, and this gene was designated sanF (GenBank Accession No. AF223971). The function of the sanF gene was studied by a strategy of gene disruption, and the resulting sanF mutants lost the ability to synthesize biologically active nikkomycin, indicating that sanF is essential for nikkomycin biosynthesis.
Received: 17 April 2000 / Accepted: 23 May 2000 相似文献
15.
Luo H Wang Y Wang H Yang J Yang Y Huang H Yang P Bai Y Shi P Fan Y Yao B 《Applied microbiology and biotechnology》2009,82(3):453-461
Using degenerate polymerase chain reaction (PCR) and thermal asymmetric interlaced PCR, a 1,347-bp full-length complementary
DNA fragment encompassing the gene man5A, which encodes a 429-amino acid β-mannanase with a calculated mass of 46.8 kDa, was cloned from acidophilic Bispora sp. MEY-1. The deduced amino acid sequence (catalytic domain) displayed highest identity (54.1%) with the Emericella nidulans endo-β-1,4-d-mannanase, a member of the glycoside hydrolase family 5. Recombinant MAN5A was overexpressed in Pichia pastoris, and its activity in the culture medium reached 500 U ml−1. The enzyme was acidophilic, with highest activity at pH 1.0–1.5, lower than any known mannanases, and optimal temperature
for activity was 65°C. MAN5A had good pH adaptability, excellent thermal and pH stability, and high resistance to both pepsin
and trypsin. The specific activity, K
m, and V
max for locust bean gum substrate was 3,373 U mg−1, 1.56 mg ml−1, and 6,587.6 μmol min−1 mg−1, respectively. The enzymatic activity was not significantly affected by ions such as Ca2+, Cr3+, Co2+, Zn2+, Na+, K+, and Mg2+ and enhanced by Ni2+, Fe3+, Mn2+ and Ag+. These favorable properties make MAN5A a potential candidate for use in various industrial applications. 相似文献
16.
17.
F. Chen F. -Y. Zhang X.-C. Xia Z.-D. Dong D.-Q. Cui 《Molecular breeding : new strategies in plant improvement》2012,29(2):371-378
Kernel hardness is one of the most important factors determining the milling and processing quality of bread wheat (Triticum aestivum L.). In the present study, 267 wheat cultivars and advanced lines from the Yellow and Huai Valley of China, CIMMYT, Russia
and Ukraine were used for identification of SKCS (Single Kernel Characterization System) hardness and puroindoline alleles.
Results indicated that Pinb-D1b is the most popular genotype in wheat cultivars from the Yellow and Huai Valley, Russia and Ukraine, whereas PINA null is
a predominant genotype in wheat cultivars and advanced lines from CIMMYT. Molecular characterization of PINA-null alleles
indicated that one Chinese landrace Chiyacao had the allele Pina-D1l with a single nucleotide C deletion at position 265 in Pina coding region based on sequencing results, and 35 of 39 PINA-null alleles belonged to Pina-D1b according to PCR amplification with the sequence-tagged site (STS) marker Pina-N developed previously. The remaining three cultivars (Jiangdongmen, Heshangtou and Hongquanmang from China) with PINA-null
alleles were characterized at the DNA level by a primer walking strategy, and the results showed that all three cultivars
with PINA-null alleles possessed a uniform 10,415-bp deletion from −5,117 bp to +5,298 bp (ATG codon references zero), designated
as Pina-D1r. Correspondingly, an STS marker Pina-N2 with an expected fragment size of 436-bp spanning the 10,415-bp deletion was developed for detection of the Pina-D1r allele. This study provided a useful molecular marker for straightforward detection of one of the PINA-null alleles and would
also be helpful to further understand the molecular and genetic basis of kernel hardness in bread wheat. 相似文献
18.
Barley zygote protoplasts were mechanically isolated, embedded in agarose droplets, and microinjected with a rice actin promoter Act1–gusA-nos gene construct. On average 62% of the cells survived the injection and of these 55% continued development into embryo-like structures and eventually to plants. PCR screening for the presence of a 307-bp fragment in the middle of the gusA gene showed that on average 21% of the derived structures contained this fragment. However, among the hundreds of injected zygotes, derived structures and regenerants we only found significant GUS expression in two cases (embryo-like structures nine days after injection). Two lines of green plants, derived from zygotes microinjected with linearized plasmid (line A147-1) or an isolated Act1–gusA-nos gene cassette (line A166-h) proved to be transgenic. Line A147-1 appeared to contain a single and intact copy of the expression cassette but a PCR based progeny analysis indicated the presence of additional shorter fragments of the cassette. Line A166-h appeared to contain a single fragment of the gusA gene that was transferred to the progeny as a single Mendelian trait. One additional fragment of the gusA gene was identified in this line. The present data show that transformation of barley by microinjection of DNA into isolated zygotes is feasible but also that gene expression rarely is achieved, possibly due to degradation of the introduced DNA. 相似文献
19.
Rahimi Z Ahmadian Z Akramipour R Vaisi-Raygani A Rahimi Z Parsian A 《Molecular biology reports》2012,39(3):2195-2200
In order to determine the influence of polymorphism in thymidylate synthase (TS 28-bp repeat) and methionine synthase (MS
A2756G) genes on the susceptibility to acute lymphoblastic leukemia (ALL), 73 children with ALL and 128 age and sex matched
unrelated healthy individuals from the Kermanshah Province of Iran were screened. The genotyping of TS 28-bp repeat and MS
A2756G polymorphisms were performed by polymerase chain reaction (PCR) and PCR–RFLP, respectively. The frequency of TS 2R
allele in patients and controls were 41.5 and 38%, respectively (Odds ratios (OR) = 1.13, 95%CI 0.73–1.74, P = 0.56). The allelic frequency of G allele of MS was higher (25%) in patients compared with healthy subjects (23%) (OR = 1.09,
95%CI 0.67–1.75, P = 0.71). Considering MS AA and TS 3R3R genotypes as reference indicated that individuals with MS GG + TS 2R2R genotypes have
1.3-fold increase in the risk of ALL (OR = 1.3, 95%CI 0.6–2.7, P = 0.5). Our results showed that neither TS 28-bp repeat nor MS A2756G polymorphisms are risk factors for susceptibility to
ALL in Western Iran. 相似文献
20.
Shi H Yin X Wu M Tang C Zhang H Li J 《Journal of industrial microbiology & biotechnology》2012,39(2):347-357
Using 3′ and 5′ rapid amplification of cDNA ends methods, the full-length cDNA sequence encoding an endo-1,4-β-glucanase of Aspergillus usamii E001 (abbreviated as AuCel12A) was amplified from the total RNA. The clone cDNA sequence of the gene encoding the AuCel12A,
named as Aucel12A, is 1,027 bp in length harboring 5′ and 3′ non-coding regions, as well as a 720 bp of open reading frame that encodes a 16-aa
signal peptide, and a 223-aa mature AuCel12A with a theoretical M.W. of 24,294 Da, a calculated pI of 4.15, and one putative N-glycosylation site. The complete DNA sequence of the gene Aucel12A was amplified from the genomic DNA of A. usamii E001 by using the conventional PCR and pUCm-T vector-mediated PCR initially developed in our lab. The clone DNA sequence
is 1,576 bp in length, consisting of a 5′ flanking regulatory region, three exons, and two introns with sizes of 50 and 66 bp.
The cDNA fragment encoding the mature AuCel12A was expressed in a fully active form in Pichia pastoris. One P. pastoris transformant expressing the highest recombinant AuCel12A (rAuCel12A) activity, labeled as P. pastoris GSCel2-1, was chosen for subsequent studies. Integration of the Aucel12A into P. pastoris genome was confirmed by PCR analysis using 5′- and 3′-AOX1 primers. SDS-PAGE and enzyme activity assays demonstrated that the rAuCel12A, a glycosylated protein with an apparent M.W.
of 27.0 kDa and a carbohydrate content of 4.82%, was secreted into the culture medium. The purified rAuCel12A displayed the
highest activity at pH 5.0 and 60°C. It was highly stable at a pH range of 3.5–7.0, and at a temperature of 55°C or below.
Its activity was not significantly affected by an array of metal ions and EDTA, but inhibited by Ag+, Hg2+ and Fe2+. The K
m and V
max of the rAuCel12A, towards carboxymethylcellulose-Na (CMC-Na) at pH 5.0 and 50°C were 4.85 mg/ml and 160.5 U/mg, respectively. 相似文献