共查询到20条相似文献,搜索用时 15 毫秒
1.
T Murai M Ueda M Yamamura H Atomi Y Shibasaki N Kamasawa M Osumi T Amachi A Tanaka 《Applied microbiology》1997,63(4):1362-1366
We have engineered the cell surface of the yeast Saccharomyces cerevisiae by anchoring active glucoamylase protein on the cell wall, and we have endowed the yeast cells with the ability to utilize starch directly as the sole carbon source. The gene encoding Rhizopus oryzae glucoamylase with its secretion signal peptide was fused with the gene encoding the C-terminal half (320 amino acid residues from the C terminus) of yeast alpha-agglutinin, a protein involved in mating and covalently anchored to the cell wall. The constructed plasmid containing this fusion gene was introduced into S. cerevisiae and expressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter from S. cerevisiae. The glucoamylase activity as not detected in the culture medium, but it was detected in the cell pellet fraction. The glucoamylase protein transferred to the soluble fraction from the cell wall fraction after glucanase treatment but not after sodium dodecyl sulfate treatment, indicating the covalent binding of the fusion protein to the cell wall. Display of the fused protein was further confirmed by immunofluorescence microscopy and immunoelectron microscopy. The transformant cells could surely grow on starch as the sole carbon source. These results showed that the glucoamylase was anchored on the cell wall and displayed as its active form. This is the first example of an application of cell surface engineering to utilize and improve the metabolic ability of cells. 相似文献
2.
Ye K Shibasaki S Ueda M Murai T Kamasawa N Osumi M Shimizu K Tanaka A 《Applied microbiology and biotechnology》2000,54(1):90-96
An engineered yeast with emission of fluorescence from the cell surface was constructed. Cell surface engineering was applied
to display a visible reporter molecule, green fluorescent protein (GFP). A glucose-inducible promoter GAPDH as a model promoter was selected to control the expression of the reporter gene in response to environmental changes. The
GFP gene was fused with the gene encoding the C-terminal half of α-agglutinin of Saccharomyces cerevisiae having a glycosylphosphatidylinositol anchor attachment signal sequence. A secretion signal sequence of the fungal glucoamylase
precursor protein was connected to the N-terminal of GFP. This designed gene was integrated into the TRP1 locus of the chromosome of S. cerevisiae with homologous recombination. Fluorescence microscopy demonstrated that the transformant cells emitted green fluorescence
derived from functionally expressed GFP involved in the fusion molecule. The surface display of GFP was further verified by
immunofluorescence labeling with a polyclonal antibody (raised in rabbits) against GFP as the first antibody and Rhodamine
Red-X-conjugated goat anti-rabbit IgG as the second antibody which cannot penetrate into the cell membrane. The display of
GFP on the cell surface was confirmed using a confocal laser scanning microscope and by measuring fluorescence in each cell
fraction obtained after the subcellular fractionation. As GFP was proved to be displayed as an active form on the cell surface,
selection of promoters will endow yeast cells with abilities to respond to changes in environmental conditions, including
nutrient concentrations in the media, through the emission of fluorescence.
Received: 23 August 1999 / Received revision: 16 November 1999 / Accepted: 29 November 1999 相似文献
3.
Murai T Ueda M Shibasaki Y Kamasawa N Osumi M Imanaka T Tanaka A 《Applied microbiology and biotechnology》1999,51(1):65-70
The construction of a whole-cell biocatalyst with its sequential reaction has been performed by the genetic immobilization
of two amylolytic enzymes on the yeast cell surface. A recombinant strain of Saccharomyces cerevisiae that displays glucoamylase and α-amylase on its cell surface was constructed and its starch-utilizing ability was evaluated.
The gene encoding Rhizopus oryzae glucoamylase, with its own secretion signal peptide, and a truncated fragment of the α-amylase gene from Bacillus stearothermophilus with the prepro secretion signal sequence of the yeast α factor, respectively, were fused with the gene encoding the C-terminal
half of the yeast α-agglutinin. The constructed fusion genes were introduced into the different loci of chromosomes of S. cerevisiae and expressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The glucoamylase and α-amylase
activities were not detected in the culture medium, but in the cell pellet fraction. The transformant strain co-displaying
glucoamylase and α-amylase could grow faster on starch as the sole carbon source than the transformant strain displaying only
glucoamylase.
Received: 16 June 1998 / Received last revision: 21 August 1998 / Accepted: 3 September 1998 相似文献
4.
Seung-Moon Park Ae-Young Mo Jung-Gu Lim Hea-Jong Chung Tae-Geum Kim Kang-Ju Kim Dong-Ha Cho Moon-Sik Yang Dae-Hyuk Kim 《Biotechnology and Bioprocess Engineering》2007,12(6):690-695
The neutralizing epitope (K-COE) of the spike protein from a Korean strain of porcine epidemic diarrhea virus (PEDV) has been
shown to prevent and foster an immune response to PED, when orally adjusted. The cell surface of the budding yeast,Saccharomyces cerevisiae, was engineered to anchor the K-COE on the outer layer of the cell, and consequently, the altered yeast was applied as a
dietary complement for animal feed, with immunogenic functions. In this study, the K-COE gene (K-COE) of the Korean strain of PEDV with the signal peptide of rice amylase 1A (Ramy 1A), was fused with the gene encoding the carboxyterminal half (320 amino acid residues from the C terminus) of yeast α-agglutinin,
a mating associated protein that is anchored covalently to the cell wall. The glyceraldehyde-3-phosphate dehydrogenase (GPD) promoter was selected in order to direct the expression of the fusion construct, and the resulting recombinant plasmid was
then introduced intoS. cerevisiae. The surface display of K-COE was visualized via confocal microscopy using a polyclonal antibody against K-COE as the primary
antibody, and FITC (fluorescein isothiocyanate)-conjugated goat anti-mouse IgG as the secondary antibody. The display of the
K-COE on the cell surface was further verified via Western blot analysis using the cell wall fraction after the administration
of α-1,3-glucanase/PNGase F/β-mannosidase treatment. 相似文献
5.
K. Hamada S. Fukuchi M. Arisawa M. Baba K. Kitada 《Molecular & general genetics : MGG》1998,258(1-2):53-59
Open reading frames in the genome of Saccharomyces cerevisiae were screened for potential glycosylphosphatidylinositol (GPI)-attached proteins. The identification of putative GPI-attached
proteins was based on three criteria: the presence of a GPI-attachment signal sequence, a signal sequence for secretion and
a serine- or threonine-rich sequence. In all, 53 ORFs met these three criteria and 38 were further analyzed as follows. The
sequence encoding the 40 C-terminal amino acids of each was fused with the structural gene for a reporter protein consisting
of a secretion signal, α-galactosidase and a hemagglutinin (HA) epitope, and examined for the ability to become incorporated
into the cell wall. On this basis, 14 of fusion proteins were classified as GPI-dependent cell wall proteins because cells
expressing these fusion proteins: (i) had high levels of α-galactosidase activity on their surface; (ii) released significant
amounts of the fusion proteins from the membrane on treatment with phosphatidylinositol-specific phospholipase C (PI-PLC);
and (iii) released fusion proteins from the cell wall following treatment with laminarinase. Of the 14 identified putative
GPI-dependent cell wall proteins, 12 had novel ORFs adjacent to their GPI-attachment signal sequence. Amino acid sequence
alignment of the C-terminal sequences of the 12 ORFs, together with those of known cell wall proteins, reveals some sequence
similarities among them.
Received: 1 September 1997 / Accepted: 20 November 1997 相似文献
6.
Ae-Young Mo Seung-Moon Park Yun-Sik Kim Moon-Sik Yang Dae-Hyuk Kim 《Biotechnology and Bioprocess Engineering》2005,10(6):576-581
Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals, and reduces the phosphorus
pollution of animal waste. We have engineered the cell surface of the yeast,Saccharomyces cerevisiae by anchoring active fungal phytase on its cell wall, in order to apply it as a dietary supplement containing bioconversional
functions in animal foods and a whole cell bio-catalyst for the treatment of waste. The phytase gene (phyA) ofAspergillus niger with a signal peptide of rice amylase 1A (Ramy1A) was fused with the gene encoding the C-terminal half (320 amino acid residues from the C-terminus) of yeast α-agglutinin,
a protein which is involved in mating and is covalently anchored to the cell wall. The resulting fusion construct was introduced
intoS. cerevisiae and expressed under the control of the constitutive glyceraldehydes-3-phosphate dehydrogenase (GPD) promoter. Phytase plate
assay revealed that the surface-engineered cell exhibited a catalytically active opaque zone which was restricted to the margin
of the colony. Additionally, the phytase activity was detected in the cell fraction, but was not detected in the culture medium
when it was grown in liquid. These results indicate that the phytase was successfully anchored to the cell surface of yeast
and was displayed as its active form. The amount of recombinant phytase on the surface of yeast cells was estimated to be
16,000 molecules per cell. 相似文献
7.
Dilsen S Paul W Sandgathe A Tippe D Freudl R Thömmes J Kula MR Takors R Wandrey C Weuster-Botz D 《Applied microbiology and biotechnology》2000,54(3):361-369
A pH-auxostatic fed-batch process was developed for the secretory production of a fusion protein consisting of the pro-part
of Staphylococcus hyicus lipase and two synthetic human calcitonin (hCT) precursor repeats under the control of a xylose-inducible promotor from Staphylococcus xylosus. Using glycerol as the energy source and pH-controlled addition of yeast extract resulted in the production of 2000 mg l−1 of the fusion protein (420 mg l−1 of the recombinant hCT precursor) within 14 h, reaching 45 g l−1 cell dry mass with Staphylococcus carnosus in a stirred-tank reactor. Product titer and space-time yield (30 mg calcitonin precursor l−1 h−1) were thus improved by a factor of 2, and 4.5, respectively, compared to Escherichia coli expression-secretion systems for the production of calcitonin precursors. Two hundred grams of the fusion protein was secreted
by the recombinant S. carnosus on a 150-l scale (scale-up factor of 50) with a minimum use of technical-grade yeast extract (40 mg fusion protein g−1 yeast extract).
Received: 18 January 2000 / Received revision: 14 April 2000 / Accepted: 14 April 2000 相似文献
8.
A xylose reductase gene (xyl1) of Candida guilliermondii ATCC 20118 was cloned and characterized. The open reading frame of xyl1 contained 954 nucleotides encoding a protein of 317 amino acids with a predicted molecular mass of 36 kDa. The derived amino
acid sequence of C. guilliermondii xylose reductase was 70.4% homologous to that of Pichia stipitis. The gene was placed under the control of an alcohol oxidase promoter (AOX1) and integrated into the genome of a methylotrophic yeast, Pichia pastoris. Methanol induced the expression of the 36-kDa xylose reductase in both intracellular and secreted expression systems. The
expressed enzyme preferentially utilized NADPH as a cofactor and was functional both in vitro and in vivo. The different cofactor
specificity between P. pastoris and C. guilliermondii xylose reductases might be due to the difference in the numbers of histidine residues and their locations between the two
proteins. The recombinant was able to ferment xylose, and the maximum xylitol accumulation (7.8 g/l) was observed when the
organism was grown under aerobic conditions.
Received: 26 August 1997 / Received revision: 6 November 1997 / Accepted: 21 November 1997 相似文献
9.
C. S. Shin M. S. Hong D. Y. Kim H. C. Shin J. Lee 《Applied microbiology and biotechnology》1998,49(4):364-370
Synthesis of two recombinant proteins (human glucagon and human growth hormone) was investigated in fed-batch cultures at
high cell concentrations of recombinant Escherichia coli. The glucose-limited growth was achieved without accumulation of metabolic by-products and hence the cellular environment
is presumed invariable during growth and recombinant protein synthesis. Via exponential feeding in the two-phase fed-batch
operation, the specific cell growth rate was successfully controlled at the desired rates and the fed-batch mode employed
is considered appropriate for examining the correlation between the specific growth rate and the efficiency of recombinant
product formation in the recombinant E. coli strains. The two recombinant proteins were expressed as fusion proteins and the concentration in the culture broth was increased
to 15 g fusion growth hormone l−1 and 7 g fusion glucagon l−1. The fusion growth hormone was initially expressed as soluble protein but seemed to be gradually aggregated into inclusion
bodies as the expression level increased, whereas the synthesized fusion glucagon existed as a cytoplasmic soluble protein
during the whole induction period. The stressful conditions of cultivation employed (i.e. high-cell-density cultivation at
low growth rate) may induce the increased production of various host-derived chaperones and thereby enhance the folding efficiency
of synthesized heterologous proteins. The synthesis of the recombinant fusion proteins was strongly growth-dependent and more
efficient at a higher specific growth rate. The mechanism linking specific growth rate with recombinant protein productivity
is likely to be related to the change in cellular ribosomal content.
Received: 27 May 1997 / Received last revision: 31 October 1997 / Accepted: 21 November 1997 相似文献
10.
A plasmid (pYP17) containing a genomic DNA insert from Escherichia coli K-12 that confers the ability to hydrolyze carboxymethylcellulose (CMC) was isolated from a genomic library constructed in
the cosmid vector pLAFR3 in E. coli DH5α. A small 1.65-kb fragment, designated bcsC (pYP300), was sequenced and found to contain an ORF of 1,104 bp encoding a protein of 368 amino acid residues, with a calculated
molecular weight of 41,700 Da. BcsC carries a typical prokaryotic signal peptide of 21 amino acid residues. The predicted
amino acid sequence of the BcsC protein is similar to that of CelY of Erwinia chrysanthemi, CMCase of Cellulomonas uda, EngX of Acetobacter xylinum, and CelC of Agrobacterium tumefaciens. Based on these sequence similarities, we propose that the bcsC gene is a member of glycosyl hydrolase family 8. The apparent molecular mass of the protein, when expressed in E. coli, is approximately 40 kDa, and the CMCase activity is found mainly in the extracellular space. The enzyme is optimally active
at pH 7 and a temperature of 40° C.
Received: 6 February 1998 / Accepted: 6 November 1998 相似文献
11.
H. Okada T. Sekiya K. Yokoyama H. Tohda H. Kumagai Y. Morikawa 《Applied microbiology and biotechnology》1998,49(3):301-308
A cbh2 cDNA encoding Trichoderma reesei QM9414 cellobiohydrolase II, located on the expression vector whose copy number is controlled by the level of gentamicin,
was successfully expressed under the control of a human cytomegalovirus promoter in the fission yeast, Schizosaccharomyces pombe. The 24-amino-acid leader peptide of the cbh2 gene was recognized by the yeast, enabling the efficient secretion of the heterologous cellobiohydrolase. The transformed
S. pombe strain produced over 115 μg cellobiohydrolase proteins/ml rich medium supplemented with malt extract and 100 μg/ml gentamicin.
The molecular masses of the recombinant cellobiohydrolases, secreted as two molecular species, were estimated to be 70 kDa
and 72 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE). Deglycosylation treatments revealed that
the recombinant enzymes were overglycosylated and scarcely susceptible to α-mannosidase. The recombinant enzymes showed no
carboxymethylcellulase activity, but showed similar characteristics to those of a native enzyme purified from T. reesei in their optimum pH and temperature, pH and temperature stabilities, and V
max values toward phosphoric-acid-swollen cellulose as substrate, except that their K
m values were about fourfold higher than that of the native enzyme.
Received: 4 August 1997 / Received revision: 13 October 1997 / Accepted: 31 October 1997 相似文献
12.
Y. Inoue T. Ohta H. Tada S. Iwasa S. Udaka H. Yamagata 《Applied microbiology and biotechnology》1997,48(4):487-492
Expression/secretion vectors for the production of Fab′ and single-chain (sc) Fab′ by Bacillus brevis have been constructed. For the production of Fab′, the cDNAs encoding the L chain and Fd′ fragment (Fd with the hinge region)
of a mouse-human chimeric Fab′ against human urokinase-type plasminogen activator were fused directly with the translation-start
and signal-peptide-encoding regions of the mwp gene, the gene for one of the major cell-wall proteins of Bacillus brevis. The two fused genes were placed tandemly downstream from the promoter of the cell-wall protein gene operon (cwp) of B. brevis. For the production of scFab′, the two cDNAs were linked with a synthetic oligonucleotide encoding a flexible peptide linker
of 17 or 24 amino acids, and fused with the translation start and signal-peptide-encoding regions of the mwp gene. Fab′ was efficiently produced by B. brevis, being accumulated at a level of 100 mg/l in the culture medium in a simple shake-flask culture, which is the highest level
obtained so far for a gram-positive bacterium. On the other hand, the scFab′ remained at a level of a few milligrams per liter
in the culture medium. The Fab′ produced by B. brevis showed comparable antigen-binding activity to that of the parental antibody. The L chain and Fd′ fragment, constituting the
Fab′, had the correct N-terminal amino acid sequences. These results indicate that B. brevis is a very promising host for the production of native Ig fragments.
Received: 25 April 1997 / Received revision: 3 June 1997 / Accepted: 29 June 1997 相似文献
13.
An efficient one-step transformation method for the dimorphic yeast Yarrowia lipolytica is described. Using cells grown overnight on agar plates, the whole process is carried out within 1 h. The transformant clones
could be recovered on selective plates as early as 36–48 h after plating. The efficiency was better than 105 transformants/μg replicative plasmid DNA. Effects of cell density, dithiothreitol, heat shock, poly(ethylene glycol) 4000
concentration and the wetness of selective plates were investigated.
Received: 17 February 1997 / Received revision: 4 April 1997 / Accepted: 19 April 1997 相似文献
14.
Two δ-integration vectors were evaluated for the insertion of an inducible expression cassette (the yeast CUP1 promoter fused to the Escherichia coli lacZ structural gene, CUP1p-lacZ) and a bacterial neomycin-resistance gene (neo) into the genome of Saccharomyces cerevisiae via homologous recombination. Cells containing integrations were selected by resistance to the aminoglycoside G418. The first
vector was a traditional construct containing only one δ sequence; with this vector, the transformation efficiency and the
number of integrations per cell were quite low. The second carried two δ sequences flanking the desired insert, and the unneeded
bacterial sequences were removed by restriction-enzyme digestion immediately before transformation. When this double δ vector
was employed, the integrated copy number was more than doubled relative to the single δ system and final β-galactosidase levels
exceeded those obtained with the 2μ-based plasmid. Furthermore, the integrations appeared more stable in long-term sequential
culture (both with and without induction of the lacZ gene) than those obtained via the single δ vector.
Received: 2 December 1996 / Received revision: 21 March 1997 / Accepted: 13 April 1997 相似文献
15.
A cDNA fragment encoding the A catalytic domain of the Neocallimastix frontalis endoxylanase XYN3 was amplified and cloned by the polymerase chain reaction technique. The xyn3A DNA fragment was inserted between the Saccharomyces cerevisiae phosphoglycerate kinase gene promoter and terminator sequences on a multicopy episomal plasmid for Kluyveromyces lactis. The XYN3A domain was successfully expressed in K. lactis and functional endoxylanase was secreted by the yeast cells with the K. lactis killer toxin secretion signal. The XYN3A domain was also expressed in a strain of Penicillium roqueforti as a fusion protein (ShBLE::XYN3A) of the phleomycin-resistance gene product and the endoxylanase. Active endoxylanase was
efficiently secreted from the fungal cells with the Trichoderma viride cellobiohydrolase (CBH1) secretion signal and processed by a related KEX2 endoprotease of the secretion pathway. Several
differently glycosylated forms of the recombinant enzymes were secreted by the yeast and the filamentous fungus.
Received: 10 November 1998 / Received revision: 8 March 1999 / Accepted: 14 March 1999 相似文献
16.
The secretion of proteins from Bacillus subtilis was studied under physiologically well-defined conditions in continuous cultures at a range of specific growth rates. The
kinetics of secretion was analysed by using pulse-chase and immunoprecipitation techniques that allowed both processing and
release to be monitored. Growth conditions were selected that were known to lead to significant changes in the anionic polymer
composition of the cell wall. Under magnesium limitation only low levels of native proteins were released into the growth
medium. In contrast, much higher amounts of released protein were observed under phosphate limitation. Although synthesis
of native secretory proteins appeared to be highly regulated, only minor changes in the secretion of heterologous proteins
were detected. Comparable kinetics of protein release of cells grown under different conditions indicated similar cell wall
permeabilities. The large changes in the amounts of released proteins were not reflected in the production of chaperones and
components required for protein secretion. The data suggest that the capacity of the secretion machinery is not a major limiting
step in the export of native secretory proteins.
Received: 23 September 1997 / Received revision: 10 November 1997 / Accepted: 16 November 1997 相似文献
17.
I. Faus C. del Moral N. Adroer J. L. del Río C. Patiño H. Sisniega C. Casas J. Bladé V. Rubio 《Applied microbiology and biotechnology》1998,49(4):393-398
A recombinant form of the sweet-tasting protein thaumatin has been produced in the filamentous fungus Aspergillus niger var. awamori. Expression cassettes containing a synthetic gene encoding thaumatin II were prepared and used to transform Aspergillus niger var. awamori strain NRRL312. Several fungal strains capable of synthesizing and secreting thaumatin into the culture medium were generated,
and their production capabilities were determined, first in shake flasks and later in a laboratory fermentor. We report the
expression and secretion of thaumatin in concentrations of 5–7 mg/l. This recombinant thaumatin is sweet.
Received: 7 October 1997 / Received revision: 21 November 1997 / Accepted: 21 November 1997 相似文献
18.
M. L. Rúa H. Atomi C. Schmidt-Dannert R. D. Schmid 《Applied microbiology and biotechnology》1998,49(4):405-410
An efficient expression system for the previously only weakly expressed thermophilic lipase BTL2 (Bacillus thermocatenulatus lipase 2) was developed for the production of large amounts of lipase in Escherichia coli. Therefore, the gene was subcloned in the pCYTEXP1 (pT1) expression vector downstream of the temperature-inducible λ promoter
PL. Three different expression vectors were constructed: (i) pT1-BTL2 containing the mature lipase gene, (ii) pT1-preBTL2 containing the prelipase gene and (iii) pT1-OmpABTL2 containing the mature lipase gene fused to the signal peptide of the OmpA protein, the major outer membrane
protein of E. coli. With pT1-BTL2 and pT1-preBTL2, comparable expression levels of 7000–9000 U/g cells were obtained independently of the E. coli host. In contrast, with E. coli JM105 harbouring pT1-OmpABTL2, 660 000 soluble lipase U/g cells was produced, whereas, with E. coli DH5α and BL321, production levels of 30 000 U/g cells were achieved. However, most of the lipase remained insoluble but active
after cell breakage because of the unprocessed OmpA signal peptide. A simple cholate extraction followed by proteinase K cleavage
and ultrafiltration allowed the isolation of 1.15 × 106 units of 90% pure mature lipase/wet cells.
Received: 29 August 1997 / Received revision: 17 November 1997 / Accepted: 18 November 1997 相似文献
19.
Poly(hydroxybutyric acid) (PHB) was produced by a selectant of Azotobacter beijerinckii in media containing only organic nitrogen sources such as N substrates. The chosen compounds were casein peptone, yeast extract,
casamino acids and urea, each combined with carbon substrates glucose or sucrose. The PHB was synthesized under growth-associated
conditions. The concentrations amounted to more than 50% of cell dry mass on casein peptone/glucose as well as urea/glucose
medium within 45 h fermentation time. Corresponding to these yields, productivities of about 0.8 g PHB l−1 h−1 were discovered. The highest values increased to 1.06 g PHB l−1 h−1 on casein peptone/glucose medium and 1.1 g PHB l−1 h−1 on yeast extract/glucose medium after a period of 20 h. It was found that oxygen limitation was essential for successful
product formation, as demonstrated earlier. These data from basic research may support further investigations into the use
of technical proteins from renewable sources as substrates for PHB production by a strain of A. beijerinckii.
Received: 3 June 1997 / Received revision: 29 August 1997 / Accepted: 15 September 1997 相似文献
20.
Overexpression of a cytosolic hydroxymethylglutaryl-CoA reductase leads to squalene accumulation in yeast 总被引:4,自引:0,他引:4
The enzyme 3-hydroxy-3-methylglutaryl-coenzyme-A (HMG-CoA) reductase is known as the rate-limiting enzyme in early sterol
biosynthesis in eukaryotic cells. To eliminate this regulation in the yeast Saccharomyces cerevisiae, a truncated HMG1 gene, producing a form of the enzyme that lacks the membrane-binding region (i.e. amino acids 1–552), was constructed and
overexpressed in this yeast. The transformed strains accumulated large amounts of the sterol precursor squalene, while the
levels of ergosterol and a number of other sterol compounds were only slightly elevated. These findings suggest that HMG-CoA
reductase is not the only rate-limiting step in sterol synthesis and its overexpression cannot significantly influence this
pathway beyond the sterol precursor squalene.
Received: 9 June 1997 / Received revision: 1 September 1997 / Accepted: 19 September 1997 相似文献