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1.
The purpose of our study was to evaluate the correlation between the b-fibrinogen gene –148C/T and –455G/A polymorphisms and susceptibility to coronary artery disease in the Chinese population using a meta–analytic approach. Eligible studies about this correlation were identified by searching the PubMed, EMBASE, and CNKI databases. Of the 13 identified, 7 (with 1488 cases and 1234 controls) involved the –148C/T polymorphism and 9 (with 1023 cases and 1081 controls) involved the –455G/A polymorphism. No publication bias was detectable and heterogeneity testing found significant differ-ences between the ORs for both groups of studies. The combined OR for the 7 studies on susceptibility to coronary artery disease in –148T allele carriers compared to the –148C/C wild-type homozygotes was 1.31 (95%CI: 0.94-1.84, P=0.11). The combined OR for the 9 studies on susceptibility to coronary artery disease in –455A allele carriers compared to the –455G/G wild-type homozygotes was 1.75 (95%CI: 1.24-2.46, P=0.001). Our results suggest the absence of an association between the b-fibrinogen gene –148C/T polymorphism and susceptibility to coronary artery disease and the possibility that –455G/A polymorphism (in particular, allele A) increases susceptibility to this disease in the Chinese population. 相似文献
2.
从大熊猫基因组中克隆了FOXL2基因,并对其进行序列分析及原核表达和真核表达.将FOXL2编码区序列克隆到原核表达载体pET-32a(+)中,转化大肠杆菌BL21,经IPTG诱导表达出FOXL2重组蛋白.成功构建了真核表达载体FOXL2-pcDNA3.1/V5-His C,并通过脂质体介导转染HEK293细胞,Western blot检测FOXL2蛋白表达.SDS-PAGE分析表明,FOXL2重组蛋白在诱导4h后表达量达到峰值,其大小约为58.9 kDa,Western blot分析结果显示重组蛋白能够被抗His单克隆抗体特异性识别.FOXL2基因的克隆及其表达为进一步进行FOXL2的活性检测以及应用研究奠定了基础. 相似文献
3.
We have investigated the phylogenetic relationships of monotremes and marsupials using nucleotide sequence data from the
neurotrophins; nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3). The study included
species representing monotremes, Australasian marsupials and placentals, as well as species representing birds, reptiles,
and fish. PCR was used to amplify fragments encoding parts of the neurotrophin genes from echidna, platypus, and eight marsupials
from four different orders. Phylogenetic trees were generated using parsimony analysis, and support for the different tree
structures was evaluated by bootstrapping. The analysis was performed with NGF, BDNF, or NT-3 sequence data used individually
as well as with the three neurotrophins in a combined matrix, thereby simultaneously considering phylogenetic information
from three separate genes. The results showed that the monotreme neurotrophin sequences associate to either therian or bird
neurotrophin sequences and suggests that the monotremes are not necessarily related closer to therians than to birds. Furthermore,
the results confirmed the present classification of four Australasian marsupial orders based on morphological characters,
and suggested a phylogenetic relationship where Dasyuromorphia is related closest to Peramelemorphia followed by Notoryctemorphia
and Diprotodontia. These studies show that sequence data from neurotrophins are well suited for phylogenetic analysis of mammals
and that neurotrophins can resolve basal relationships in the evolutionary tree.
Received: 27 January 1997 / Accepted: 20 March 1997 相似文献
4.
Vladimir V. Aleshin Irina A. Milyutina Olga S. Kedrova Natalia S. Vladychenskaya Nikolai B. Petrov 《Journal of molecular evolution》1998,47(5):597-605
Phylogenetic relationships of nematodes, nematomorphs, kinorhynchs, priapulids, and some other major groups of invertebrates
were studied by 18S rRNA gene sequencing. Kinorhynchs and priapulids form the monophyletic Cephalorhyncha clade that is the
closest to the coelomate animals. When phylogenetic trees were generated by different methods, the position of nematomorphs
appeared to be unstable. Inclusion of Enoplus brevis, a representative of a slowly evolving nematode lineage, in the set of analyzed species refutes the tree patterns, previously
derived from molecular data, where the nematodes appear as a basal bilateral lineage. The nematodes seem to be closer to the
coelomate animals than was speculated earlier. According to the results obtained, nematodes, nematomorphs, tardigrades, arthropods,
and cephalorhynchs are a paraphyletic association of closely related taxa.
Received: 1 December 1997 / Accepted: 9 April 1998 相似文献
5.
William S. Alverson Barbara A. Whitlock Reto Nyffeler Clemens Bayer David A. Baum 《American journal of botany》1999,86(10):1474-1486
The monophyly of the group comprising the core malvalean families, Bombacaceae, Malvaceae, Sterculiaceae, and Tiliaceae, was recently confirmed by molecular studies, but the internal structure of this clade is poorly understood. In this study, we examined sequences of the chloroplast ndhF gene (aligned length 2226 bp) from 70 exemplars representing 35 of the 39 putative tribes of core Malvales. The monophyly of one traditional family, the Malvaceae, was supported in the trees resulting from these data, but the other three families, as traditionally circumscribed, are nonmonophyletic. In addition, the following relationships were well supported: (1) a clade, /Malvatheca, consisting of traditional Malvaceae and Bombacaceae (except some members of tribe Durioneae), plus Fremontodendron and Chiranthodendron, which are usually treated as Sterculiaceae; (2) a clade, /Malvadendrina, supported by a unique 21-bp (base pair) deletion and consisting of /Malvatheca, plus five additional subclades, including representatives of Sterculiaceae and Tiliaceae, and Durionieae; (3) a clade, /Byttneriina, with genera traditionally assigned to several tribes of Tiliaceae, plus exemplars of tribes Byttnerieae, Hermannieae, and Lasiopetaleae of Sterculiaceae. The most striking departures from traditional classifications are the following: Durio and relatives appear to be more closely related to Helicteres and Reevesia (Sterculiaceae) than to Bombacaceae; several genera traditionally considered as Bombacaceae (Camptostemon, Matisia, Phragmotheca, and Quararibea) or Sterculiaceae (Chiranthodendron and Fremontodendron) appear as sister lineages to the traditional Malvaceae; the traditional tribe Helictereae (Sterculiaceae) is polyphyletic; and Sterculiaceae and Tiliaceae, as traditionally circumscribed, represent polyphyletic groups that cannot sensibly be maintained with their traditional limits for purposes of classification. We discuss morphological characters and conclude that there has been extensive homoplasy in characters previously used to delineate major taxonomic groups in core Malvales. The topologies here also suggest that /Malvatheca do not have as a synapormophy monothecate anthers, as has been previously supposed but, instead, may be united by dithecate, transversely septate (polysporangiate) anthers, as found in basal members of both /Bombacoideae and /Malvoideae. Thus, “monothecate” anthers may have been derived at least twice, independently, within the /Bombacoideae (core Bombacaceae) and /Malvoideae (traditional Malvaceae). 相似文献
6.
7.
A 314-bp fragment of the mitochondrial 12S rRNA gene from 21 cestodes species of eight families was synthesized by PCR with
specially designed primers. These allowed amplification of parasite DNA without concomitant synthesis of host DNA. Phylogenetic
trees were inferred from the sequence data using three methods (maximum parsimony, maximum likelihood, and Fitch–Margoliash).
At the major nodes all three trees were similar. For the first time the genus Mesocestoides could be arranged into the Cyclophyllidea and a narrow relationship between the Mesocestoididae, Taeniidae, Hymenolepididae,
Anoplocephalidae, and Dipylidiidae was shown. Members of the families Catenotaeniidae and a cluster of two families (Hymenolepididae
and Dilepididae) form two monophyletic groups which derive prior to the remaining families of this phylogenetic study. A third
and a fourth clear monophyletic group were formed by the Taeniidae and by the Mesocestoididae. A high degree of variation
within the examined 304-bp fragment was observed between two isolates of Taenia taeniaeformis, supporting often discussed genetic heterogeneity within this species. In contrast, only one nucleotide exchange was found
in 23 isolates of Echinococcus multilocularis of various geographic origin, indicating that this species is genetically homogenous.
Received: 1 October 1997 / Accepted: 4 December 1997 相似文献
8.
Short Retroposons of the B2 Superfamily: Evolution and Application for the Study of Rodent Phylogeny
Short retroposons can be used as natural phylogenetic markers. By means of hybridization and PCR analysis, we demonstrate
that B2 retroposon copies are present only in the three rodent families: Muridae, Cricetidae, and Spalacidae. This observation
highlights the close phylogenetic relation between these families. Two novel B2-related retroposon families, named DIP and
MEN elements, are described. DIP elements are found only in the genomes of jerboas (family Dipodidae) and birch mice (family
Zapodidae), demonstrating the close relationship between these rodents. MEN element copies were isolated from the squirrel,
Menetes berdmorei, but were not detected in three other species from the family Sciuridae. The MEN element has an unusual dimeric structure:
the left and right monomers are B2- and B1-related sequences, respectively. Comparison of the B2, DIP, MEN, and 4.5S1 RNA elements revealed an 80-bp core sequence located at the beginning of the B2 superfamily retroposons. This observation
suggests that these retroposon families descended from a common progenitor. A likely candidate for this direct progenitor
could be the ID retroposon.
Received: 20 December 1996 / Accepted: 17 June 1997 相似文献
9.
Molecular Data from the 16S rRNA Gene for the Phylogeny of Pectinidae (Mollusca: Bivalvia) 总被引:17,自引:0,他引:17
The phylogenetic relationships among the species belonging to the family Pectinidae are still an issue of debate. The mitochondrial
DNA sequences from the large ribosomal RNA gene may be of great value for systematic and phylogenetic studies within families.
Partial sequences of the 16S rRNA gene were obtained for the scallop species Adamussium colbecki, Aequipecten opercularis, Chlamys glabra, C. islandica, C. varia, and Pecten jacobeus and compared with the published sequence of Pecten maximus. The present molecular data show that Chlamys are polyphyletic and do not support the assignment of these species to the two subfamilies Chlamydinae and Pectininae. Moreover,
the minimal genetic distance between P. maximus and P. jacobeus suggests that they could belong to the same species.
Received: 24 May 1999 / Accepted: 1 September 1999 相似文献
10.
Bujnicki JM 《Journal of molecular evolution》2000,50(1):39-44
To date all attempts to derive a phyletic relationship among restriction endonucleases (ENases) from multiple sequence alignments
have been limited by extreme divergence of these enzymes. Based on the approach of Johnson et al. (1990), I report for the
first time the evolutionary tree of the ENase-like protein superfamily inferred from quantitative comparison of atomic coordinates
of structurally characterized enzymes. The results presented are in harmony with previous comparisons obtained by crystallographic
analyses. It is shown that λ-exonuclease initially diverged from the common ancestor and then two ``endonucleolytic' families
branched out, separating ``blunt end cutters' from ``5′ four-base overhang cutters.' These data may contribute to a better
understanding of ENases and encourage the use of structure-based methods for inference of phylogenetic relationship among
extremely divergent proteins. In addition, the comparison of three-dimensional structures of ENase-like domains provides a
platform for further clustering analyses of sequence similarities among different branches of this large protein family, rational
choice of homology modeling templates, and targets for protein engineering.
Received: 14 June 1999 / Accepted: 11 August 1999 相似文献
11.
The origins of fungal group I introns within nuclear small-subunit (nSSU) rDNA are enigmatic. This is partly because they
have never been reported in basal fungal phyla (Zygomycota and Chytridiomycota), which are hypothesized to be ancestral to
derived phyla (Ascomycota and Basidiomycota). Here we report group I introns from the nSSU rDNA of two zygomycete fungi, Zoophagus insidians (Zoopagales) and Coemansia mojavensis (Kickxellales). Secondary structure analyses predicted that both introns belong to the IC1 subgroup and that they are distantly
related to each other, which is also suggested by different insertion sites. Molecular phylogenetic analyses indicated that
the IC1 intron of Z. insidians is closely related to the IC1 intron inserted in the LSU rDNA of the basidiomycete fungus Clavicorona taxophila, which strongly suggests interphylum horizontal transfer. The IC1 intron of C. mojavensis has a low phylogenetic affinity to other fungal IC1 introns inserted into site 943 of nSSU rDNA (relative to E. coli 16S rDNA). It is noteworthy that this intron contains a putative ORF containing a His–Cys box motif in the antisense strand,
a hallmark for nuclear-encoded homing endonucleases. Overall, molecular phylogenetic analyses do not support the placement
of these two introns in basal fungal IC1 intron lineages. This result leads to the suggestion that fungal IC1 introns might
have invaded or been transferred laterally after the divergence of the four major fungal phyla.
Received: 8 February 2001 / Accepted: 1 November 2001 相似文献
12.
M. B. Slabaugh G. M. Huestis J. Leonard J. L. Holloway C. Rosato V. Hongtrakul N. Martini R. Toepfer M. Voetz J. Schell S. J. Knapp 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):400-408
Gene sequences are rapidly accumulating for many commercially and scientifically important plants. These resources create
the basis for developing sequence-based markers for mapping and tracking known (candidate) genes, thereby increasing the utility
of genetic maps. Members of most of the gene families underlying the synthesis of seed oil fatty acids have been cloned from
the medium-chain oilseed Cuphea. Allele-specific-PCR (AS-PCR) and single-strand conformational polymorphism (SSCP) markers were developed for 22 fatty acid
synthesis genes belonging to seven gene families of Cuphea using homologous and heterologous DNA sequences. Markers were developed for 4 fatty-acyl-acyl carrier protein thioesterase,
2 β-ketoacyl-acyl carrier protein synthase I, 4 β-ketoacyl-acyl carrier protein synthase II, 3 β-ketoacyl-acyl carrier protein
synthase III, 3 acyl carrier protein, 2 β-ketoacyl-acyl carrier protein reductase, and 4 enoyl-acyl carrier protein reductase
loci. Eighty-eight percent (14 of 16) of the SSCP loci were polymorphic, whereas only 9% (2 of 22) of the AS-PCR loci were
polymorphic. These markers were mapped using a Cuphea viscosissima×C. lanceolata F2 population and produced linkage groups of 10, 3, and 2 loci (3 loci segregated independently). The 10-locus linkage group
had every gene but one necessary for the synthesis of 2- to 16-carbon fatty acids from acetyl-CoA and malonyl-ACP (the missing
gene family was not mapped). SSCP analysis has broad utility for DNA fingerprinting and mapping genes and gene families.
Received: 3 May 1996 / Accepted: 30 August 1996 相似文献
13.
Alessandra Bonci Alessandra Chiesurin Patrizia Muscas Gian Maria Rossolini 《Journal of molecular evolution》1997,44(3):299-309
The structure of a Salmonella enterica serovar typhi gene located within the fim gene cluster and encoding a putative periplasmic chaperone-like protein involved in the assembly of type 1 pili was determined.
This gene, named fimC, has the ability to encode a 26-kDa polypeptide which is similar, at the sequence level, to the PapD periplasmic chaperonin
mediating the assembly of P pili of Escherichia coli, as well as to other periplasmic chaperone-like proteins involved in the biogenesis of pili or capsule-like structures of
various Gram-negative bacteria. A comprehensive search through the literature and sequence databases identified 31 (putative)
bacterial proteins that can be included in this protein family on the basis of sequence similarity. Results of a multiple
sequence comparison analysis showed that several residues, including most of those known to be critical in maintaining the
three-dimensional structure of PapD, are either conserved or conservatively substituted in all these proteins, suggesting
an overall similar folding for all of them. It was also evident that members of this family are clustered into different subfamilies
according to structural and phyletic data.
Received: 15 February 1996 / Accepted: 3 October 1996 相似文献
14.
Phylogenetic relationships among the Japanese papilionid butterflies were analyzed by comparing 783 nucleotide sequences
of the mitochondrial gene encoding NADH dehydrogenase subunit 5 (ND5). Phylogenetic trees of the representative species from each family in the superfamily Papilionoidea revealed that the species
of the family Papilionidae and those of all other families formed distinct clusters, with a few species of the family Hesperiidae
(Hesperioidea) as an outgroup. In the phylogenetic trees of most Japanese species of the family Papilionidae with Nymphalis xanthomelas (Nymphalidae) as an outgroup, the tribe Parnassiini (Parnassiinae) formed a cluster, and the rest formed the other cluster
in which the tribe Zerynthiini (Parnassiinae) and the subfamily Papilioninae formed different subclusters. In the Papilioninae
cluster, the tribes Troidini and Graphiini formed a subcluster, and the tribe Papilionini formed the other subcluster. These
results generally agree with the traditional classification of the papilionid butterflies based on their morphological characteristics
and support the proposed evolutionary genealogy of the butterflies based on their morphology, behavior, and larval host plants,
except that the tribes Parnasiini and Zerynthiini (both Parnassiinae) are not in the same cluster.
Received: 16 March 1998 / Accepted: 28 April 1998 相似文献
15.
Carla S. Schultz Rafael A. Rodriguez Eleanor A. Chew Christian Dimaano Fung-Mee Li Marjorie D. Santos M. C. Nieto 《Immunogenetics》1998,48(4):273-282
Beta-2 microglobulin (β2m)has been shown to have an effect on the structural and functional constraints that facilitate proper class I antigen presentation.
To date, no evidence has pinpointed the β2m-specific amino acids that play an integral role in affecting structure in and around the peptide binding region of class
I. To delineate β2m amino acid positions that affect the alpha-1 helical region, we generated a series of mutant β2m proteins bearing precise amino acid substitutions. The amino acid positions chosen were based upon previous results which
demonstrated that human β2m association with H2-Ld altered the structure of the alpha-1/alpha-2 super-domain. β2m mutant proteins were used in β2m exchange assays with cells expressing H2-Ld. Following exchange, cells were assayed to determine whether mutant β2m association resulted in structural alteration of class I extracellular domains. The alteration in H2-Ld structure was evidenced by an increase in the binding of an antibody (34-1-2), specific for the alpha-1 helical region of
H2-Ld. Results demonstrated that amino acid substitutions in β2m positions 33 and 53 led to a dramatic increase in the reactivity of the alpha-1 domain-specific antibody 34-1-2. Identifying
β2m amino acid positions that influence the structure of the peptide binding region may allow for a better understanding of
cellular immune responses that center upon class I/β2m expression.
Received: 18 December 1997 / Revised: 19 February 1998 相似文献
16.
Characterization of the Hydra Lamin and Its Gene: A Molecular Phylogeny of Metazoan Lamins 总被引:4,自引:0,他引:4
Andreas Erber Dieter Riemer Helmut Hofemeister Marc Bovenschulte Reimer Stick Georgia Panopoulou Hans Lehrach Klaus Weber 《Journal of molecular evolution》1999,49(2):260-271
We report sequences for nuclear lamins from the teleost fish Danio and six invertebrates. These include two cnidarians (Hydra and Tealia), one priapulid, two echinoderms, and the cephalochordate Branchiostoma. Combining these results with earlier data on Drosophila, Caenorhabditis elegans, and various vertebrates, the following conclusions on lamin evolution can be drawn. First, all invertebrate lamins resemble
in size the vertebrate B-type lamin. Second, all lamins described previously for amphibia, birds and mammals as well as the
first lamin of a fish, characterized here, show a cluster of 7 to 12 acidic residues in the tail domain. Since this acidic
cluster is absent from all invertebrate lamins including that of the cephalochordate Branchiostoma, it was acquired with the vertebrate lineage. The larger A-type lamin of differentiated cells must have arisen subsequently
by gene duplication and insertion of an extra exon. This extra exon of the vertebrate A-lamins is the only major change in
domain organization in metazoan lamin evolution. Third, the three introns of the Hydra and Priapulus genes correspond in position to the last three introns of vertebrate B-type lamin genes. Thus the entirely different gene
organization of the C. elegans and Drosophila Dmo genes seems to reflect evolutionary drift, which probably also accounts for the fact that C. elegans has the most diverse lamin sequence. Finally we discuss the possibility that two lamin types, a constitutively expressed
one and a developmentally regulated one, arose independently on the arthropod and vertebrate lineages.
Received: 4 February 1999 / Accepted: 1 April 1999 相似文献
17.
Piero Cammarano Roberta Creti Anna M. Sanangelantoni Peter Palm 《Journal of molecular evolution》1999,49(4):524-537
A global alignment of EF-G(2) sequences was corrected by reference to protein structure. The selection of characters eligible
for construction of phylogenetic trees was optimized by searching for regions arising from the artifactual matching of sequence
segments unique to different phylogenetic domains. The spurious matchings were identified by comparing all sections of the
global alignment with a comprehensive inventory of significant binary alignments obtained by BLAST probing of the DNA and
protein databases with representative EF-G(2) sequences. In three discrete alignment blocks (one in domain II and two in domain
IV), the alignment of the bacterial sequences with those of Archaea–Eucarya was not retrieved by database probing with EF-G(2)
sequences, and no EF-G homologue of the EF-2 sequence segments was detected by using partial EF-G(2) sequences as probes in
BLAST/FASTA searches. The two domain IV regions (one of which comprises the ADP-ribosylatable site of EF-2) are almost certainly
due to the artifactual alignment of insertion segments that are unique to Bacteria and to Archaea–Eucarya. Phylogenetic trees
have been constructed from the global alignment after deselecting positions encompassing the unretrieved, spuriously aligned
regions, as well as positions arising from misalignment of the G′ and G″ subdomain insertion segments flanking the ``fifth'
consensus motif of the G domain (?varsson, 1995). The results show inconsistencies between trees inferred by alternative methods
and alternative (DNA and protein) data sets with regard to Archaea being a monophyletic or paraphyletic grouping. Both maximum-likelihood
and maximum-parsimony methods do not allow discrimination (by log-likelihood difference and difference in number of inferred
substitutions) between the conflicting (monophyletic vs. paraphyletic Archaea) topologies. No specific EF-2 insertions (or
terminal accretions) supporting a crenarchaeal–eucaryal clade are detectable in the new EF-G(2) sequence alignment. 相似文献
18.
Hiroshi Suga Daisuke Hoshiyama Shigehiro Kuraku Kazutaka Katoh Kaoru Kubokawa Takashi Miyata 《Journal of molecular evolution》1999,49(5):601-608
Animals evolved a variety of gene families involved in cell–cell communication and developmental control by gene duplication
and domain shuffling. Each family is made up of several subtypes or subfamilies with distinct structures and functions, which
diverged by gene duplications and domain shufflings before the divergence of parazoans and eumetazoans. Since the separation
from protostomes, vertebrates expanded the multiplicity of members (isoforms) in the same subfamily by further gene duplications
in their early evolution before the fish–tetrapod split. To know the dates of isoform duplications more closely, we have conducted
isolation and sequencing cDNAs encoding the fibroblast growth factor receptor, Eph, src, and platelet-derived growth factor receptor subtypes belonging to the protein tyrosine kinase family from Branchiostoma belcheri, an amphioxus, Eptatretus burgeri, a hagfish, and Lampetra reissneri, a lamprey. From a phylogenetic tree of each subfamily inferred from a maximum likelihood (ML) method, together with a bootstrap
analysis based on the ML method, we have shown that the isoform duplications frequently occurred in the early evolution of
vertebrates around or just before the divergence of cyclostomes and gnathostomes by gene duplications and possibly chromosomal
duplications.
Received: 28 April 1998 / Accepted: 30 June 1999 相似文献
19.
Summary. An assessment of the potential of proline to scavenge free radicals was made in a couple of in vitro assay systems, namely
graft co-polymerization and autooxidation of pyrogallol. Both these assays are essentially dependent upon free radical mechanisms.
Graft co-polymerization involved a ceric (Ce4+) ion- or γ-radiation-induced grafting of methyl acrylate (MA) onto a cellulose backbone. The degree of grafting, measured
gravimetrically, was taken as a measure of free radical generation. The γ-radiation-dependent grafting was far greater than
that due to Ce4+ ions. Inclusion of proline in the assay, irrespective of the initiator used, led to suppression of grafting in a concentration-dependent
manner indicating the ability of proline to scavenge free radicals. The γ-radiation-dependent grafting was also suppressed
by hydroquinone and glutathione but not by ascorbate, glycine and spermine. In contrast to graft co-polymerization, proline
did not inhibit the autooxidation of pyrogallol, a reaction involving superoxide radical generation. A subset of data constitutes
an evidence for the ability of proline to scavenge free radicals in vitro. It is implied by extension that free proline, known
to accumulate in plant tissues during abiotic stresses, would contribute to scavenging of surplus free radicals produced under
a variety of abiotic stresses.
Authors’ address: Shanti S. Sharma, Department of Biosciences, Himachal Pradesh University, Shimla 171 005, India 相似文献
20.
Hayashi S Ohno T Ito M Yokoi H 《Journal of industrial microbiology & biotechnology》2001,26(5):276-279
β-Xylosidase was extracted from Aureobasidium sp. ATCC 20524 and purified to homogeneity. The molecular mass was estimated at 411 kDa. The enzyme contained 15.3% (w/w)
carbohydrate. The optimum pH and temperature were pH 3.5 and 80°C, respectively. The enzyme was stable at pH 3.5–9 after 3
h and at 80°C after 15 min. The Michaelis constant (K
m) and maximum velocity (V
max) toward p-nitrophenyl-β-D-xyloside were 2.0 mmol l−1 and 0.94 mmol min−1 mg−1 protein, respectively. The enzyme was inhibited strongly by mercury, lead, and copper ions. Journal of Industrial Microbiology & Biotechnology (2001) 26, 276–279.
Received 02 August 2000/ Accepted in revised form 15 December 2000 相似文献