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1.
Intracellular NADPH/NADP+ ratio in cells grown on various production media with different carbon and nitrogen sources had a positive correlation with
the thymidine production. To improve thymidine production in a previously engineered E. coli strain, NAD+ kinase was overexpressed in it resulting in the NADPH/NADP+ ratio shifting from 0.184 to 0.267. The [NADH + NADP+]/[NAD+ + NADPH] ratio was, however, not significantly altered. In jar fermentation, 740 mg thymidine l−1 was produced in parental strain, while 940 mg l−1 of thymidine was produced in NAD+ kinase-expressing strain. 相似文献
2.
Yoshikazu Izumi Pijush Kanti Nath Hiroshi Yamamoto Hideaki Yamada 《Applied microbiology and biotechnology》1989,30(4):337-342
Summary A convenient and efficient method of NADPH production from NADP+ has been established using a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans IFO 3172. Using airdried cells of the bacterium, the optimum conditions for NADPH production were examined, including the cell and glucose concentrations, NADP+ concentration, pH, buffer and reaction temperature. Under suitable conditions, the conversion ratio and the amount of NADPH accumulated reached about 100% and 73 mg/ml of the reaction mixture, respectively, after 1-h reaction. Intact cells of the bacterium also showed high NADPH production even in the reaction mixture without a surfactant. The addition of Triton X-100 to the reaction mixture and freeze-thawing treatment of intact cells enhanced the production. The NADPH production method was further improved by using cells of the bacterium immobilized by entrapment in a -carrageenan gel lattice. The immobilized cells had almost the same enzymatic properties as the air-dried cells. The conditions for the continuous production of NADPH with an immobilized cell column were also investigated. NADPH was produced in a good yield (about 95%) with this continuous process. 相似文献
3.
Glutathione reductase fromSaccharomyces cerevisiae undergoes redox interconversionin situ andin vivo
José Peinado Javier Florindo J. López-Barea 《Molecular and cellular biochemistry》1992,110(2):135-143
Redox interconversion of glutathione reductase was studiedin situ withS. cerevisiae. The enzyme was more sensitive to redox inactivation in 24 hour-starved cells than in freshly-grown ones. While 5 μM NADPH
or 100 μM NADH caused 50% inactivation in normal cells in 30 min, 0.75 μM NADPH or 50 μM NADH promoted a similar effect in
starved cells. GSSG reactivated the enzyme previously inactivated by NADPH, ascertaining that the enzyme was subjected to
redox interconversion. Low EDTA concentrations fully protected the enzyme from NADPH inactivation, thus confirming the participation
of metals in such a process. Extensive inactivation was obtained in permeabilized cells incubated with glucose-6-phosphate
or 6-phosphogluconate, in agreement with the very high specific activities of the corresponding dehydrogenases. Some inactivation
was also observed with malate, L-lactate, gluconate or isocitrate in the presence of low NADP+ concentrations.
The inactivation of yeast glutathione reductase has also been studiedin vivo. The activity decreased to 75% after 2 hours of growth with glucono-δ-lactone as carbon source, while NADPH rose to 144%
and NADP+ fell to 86% of their initial values. Greater changes were observed in the presence of 1.5 μM rotenone: enzymatic activity
descended to 23% of the control value, while the NADH/NAD+ and NADPH/NADP+ ratios rose to 171% and 262% of their initial values, respectively. Such results indicate that the lowered redox potential
of the pyridine nucleotide pool existing when glucono-δ-lactone is oxidized promotesin vivo inactivation of glutathione reductase. 相似文献
4.
A sonicate of Achromobacter parvulus IFO-13182 produced NADPH from NADP+by an NADP+-linked malic enzyme [l-malate: NAD(P)+oxidoreductase, EC 1.1.1.39–40] reaction in the presence of l-malic acid and divalent metal ions. Malic enzyme of A. parvulus was stabilized by 5% l-malic acid, and activity was maintained at 60°C for 1 h. Contaminating phosphatase (orthophosphoricmonoester phosphohydrolase, EC 3.1.3.1–2) was completely inactivated by this treatment. Among the conditions tested, the optimum NADPH production was done using 36 μmol NADP+, 67 μmol l-malic acid, 63 μmol MgCl2 and 1 unit of the malic enzyme in 3 ml of 55 mm phosphate buffer (pH 7.8). Conversion ratio of NADPH from NADP+ reached 100% after 4 h incubation at 30°C and the amount of NADPH accumulated was ~12 μmol ml?1of the reaction mixture. No dephosphorylation of NADP+to NAD+or of NADPH to NADH was found by high performance liquid chromatography. The NADPH produced by such enzymatic reduction was purified by ethanol precipitation and dried in vacuo in powdered form with 97% purity, judged from the ratio of the absorbances at 340 and 260 nm. The purity of the NADPH produced was determined to be 95% from its coenzyme activity with NAD(P)+-linked glutathione reductase [NAD(P)H: oxidized-glutathione oxidoreductase, EC 1.6.4.2]. 相似文献
5.
Ferredoxin/thioredoxin system plays an important role in the chloroplastic NADP status of Arabidopsis
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Shin‐nosuke Hashida Atsuko Miyagi Maho Nishiyama Keisuke Yoshida Toru Hisabori Maki Kawai‐Yamada 《The Plant journal : for cell and molecular biology》2018,95(6):947-960
NADP is a key electron carrier for a broad spectrum of redox reactions, including photosynthesis. Hence, chloroplastic NADP status, as represented by redox status (ratio of NADPH to NADP+) and pool size (sum of NADPH and NADP+), is critical for homeostasis in photosynthetic cells. However, the mechanisms and molecules that regulate NADP status in chloroplasts remain largely unknown. We have now characterized an Arabidopsis mutant with imbalanced NADP status (inap1), which exhibits a high NADPH/NADP+ ratio and large NADP pool size. inap1 is a point mutation in At2g04700, which encodes the catalytic subunit of ferredoxin/thioredoxin reductase. Upon illumination, inap1 demonstrated earlier increases in NADP pool size than the wild type did. The mutated enzyme was also found in vitro to inefficiently reduce m‐type thioredoxin, which activates Calvin cycle enzymes, and NADP‐dependent malate dehydrogenase to export reducing power to the cytosol. Accordingly, Calvin cycle metabolites and amino acids diminished in inap1 plants. In addition, inap1 plants barely activate NADP‐malate dehydrogenase, and have an altered redox balance between the chloroplast and cytosol, resulting in inefficient nitrate reduction. Finally, mutants deficient in m‐type thioredoxin exhibited similar light‐dependent NADP dynamics as inap1. Collectively, the data suggest that defects in ferredoxin/thioredoxin reductase and m‐type thioredoxin decrease the consumption of NADPH, leading to a high NADPH/NADP+ ratio and large NADP pool size. The data also suggest that the fate of NADPH is an important influence on NADP pool size. 相似文献
6.
L. Šindelár 《Biologia Plantarum》1986,28(6):440-448
The contents of NADP+, NADPH, changes in the activity of glucose-6-phosphate dehydrogenase and some questions relating to its regulation in leaf
tissues of tobacco plants infected with PVY were studied. The content of NADP+ and the total sum of pyridine nucleotides decreased after inoculation to 15 % and 30 %, respectively, whereas the content
of NADPH increased up to the threefold control value. The contents of NADP+, NADPH and Σ(NADPH + NADP+) linearly correlated with the reproduction curve of PVY. The value of the reduction charge RC and the value of the ratio
NADPH/NADP+ sharply increased after inoculation up to tenfold and eighteenfold values, respectively, of the healthy control.
The activity of glucose-6-phosphate dehydrogenase was markedly increased in virus-infected tissues during the entire experimental
period both in crude homogenate and after its partial purification when compared with the values found in healthy control
plants. The time courses of the activity curves of both crude and partially purified enzymes were coincident and correlated
with the reproduction curve of PVY. The results indicate the involvement of coarse regulation of the activity of the enzyme
by its content without the involvement of fine regulation by the ratio NADPH/NADP+ and RC. 相似文献
7.
Two pathways serve for assimilation of ammonia inParacoccus denitrificans. Glutamate dehydrogenase (NADP+) catalyzes the assimilation at a high NH4
+ concentration. If nitrate serves as the nitrogen source, glutamate is synthesized by glutamate-ammonia ligase and glutamate
synthase (NADPH). At a very low NH4
+ concentration, all three enzymes are synthesized simultaneously. No direct relationship exists between glutamate dehydrogenase
(NADP+) and glutamate-ammonia ligase inP. denitrificans, while the glutamate synthase (NADPH) activity changes in parallel with that of the latter enzyme. Ammonia does not influence
the induction or repression of glutamate dehydrogenase (NADP+). The inner concentration of metabolites indicates a possible repression of glutamate dehydrogenase (NADP+) by the high concentration of glutamine or its metabolic products as in the case when NH4
+ is formed by assimilative nitrate reduction. No direct effect of the intermediates of nitrate assimilation on the synthesis
of glutamate dehydrogenase (NADP+) was observed. 相似文献
8.
Itaru Kojima Hiroshi Inano Bun-ichi Tamaoki 《Biochemical and biophysical research communications》1982,106(2):617-624
Using sonicated mitochondria fraction prepared from bovine adrenal glomerulosa cells, aldosterone biosynthesis from 18-hydroxycorticosterone was examined as its final step, as production of [3H]-aldosterone from [3H]-corticosterone was strongly reduced by addition of non-radioactive 18-hydroxycorticosterone during the incubation. Significant conversion of 18-hydroxycorticosterone to aldosterone by the mitochondria sonicate was observed in the presence of NADPH, but not NADP+. This reaction was almost completely inhibited in the atmosphere of 100% carbon monoxide in the presence of either NADP+, or NAD+, and significantly reduced in the mixture of carbon monoxide and oxygen (90:10) in the presence of NADPH. Several drugs, such as SU compounds, spironolactone, amphenone B and SKF 525A which affect cytochrome P-450 blocked production of aldosterone from 18-hydroxycorticosterone. From these results, we conclude that a mixed function oxidase involving a cytochrome P-450 is engaged in the final course of aldosterone biosynthesis. 相似文献
9.
Experiments designed to elucidate the nature of 17β-hydroxysteroid dehydrogenase from human red blood cells have shown that NADP+ activates and protects the enzyme, while also serving as substrate for the reaction. Enzyme activity was measured by the conversion of 17β-estradiol to estrone and by the production of NADPH with 17β-estradiol-3-sulfate as substrate. It appears that the reaction sequence is first, binding with NADP+ and second, binding with the steroid. The binding with NADP+ is essentially irreversible: the activated enzyme is completely protected against loss of activity by dilution. On dilution of the unactivated enzyme, much of the activity is lost. The bireactant rate equation of the sequential type has been restated for the case of activation by one of the reactants. Since it has been found that activation of enzyme is linear with NADP+ concentration, it follows that the Michaelis constant for the steroid substrate is independent of the concentration of NADP+ activating the enzyme. This is substantiated by the determination of the Michaelis constant for 17β-estradiol-3-sulfate from data on double-reciprocal plots of activated and unactivated enzyme with limiting amounts of steroid. The activating effect increases linearly up to a concentration of 1.2 × 10?5m of NADP+ and then levels off. The activation is highly specific for NADP+; neither NAD+, ATP, NADPH, nicotinic acid, ncr nicotinamide prevent the loss of activity after storing the enzyme for 1 hr at 37 °C. The steroid substrate appears to interfere with the activation of NADP+. 相似文献
10.
Shwu-Maan Lee Sylvia Z. Schade Clyde C. Doughty 《Biochimica et Biophysica Acta (BBA)/General Subjects》1985,841(3):247-253
NADPH and NADP+ levels were measured in rat lens from normal controls, from galactose-fed and diabetic rats during the first week of cataract formation.The level of NADPH in normal rat lens was determined to be 12.3 ± 0.4 nmol/g wet weight, and that of NADP+ 4.6 ± 0.2 nmol/g wet weight. In early cataract formation NADPH levels decreased rapidly during the first 2 days and then remained stable at 76% of control for galactose-fed and 84% for diabetic rats. NADP+ levels increased by 38% of control for galactose-fed and 54% for diabetic rats. Calculated NADPH/NADP+ ratios dropped from 3.36 ± 0.21 to 1.86 ± 0.16 in galactose fed rats, and from 2.81 ± 0.15 to 1.61 ± 0.16 in diabetic rats (P < 0.001 for both experimental groups). These data are consistent with rapid NADPH oxidation during onset of lens cataracts. No significant changes in aldose reductase enzymatic activity levels were observed in either the galactosemic or the diabetic rats during the times measured. 相似文献
11.
Keiichi Kobayashi Takasumi Hattori Rie Hayashi 《Bioscience, biotechnology, and biochemistry》2013,77(7):1246-1253
In the tricarboxylic acid (TCA) cycle, NADP+-specific isocitrate dehydrogenase (NADP+-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form α-ketoglutaric acid with NADP+ as a cofactor. We constructed an NADP+-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP+-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP+-ICDH activity. Therefore, NADP+-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering. 相似文献
12.
Glucose-6-phosphate dehydrogenase (d-glucose-6-phosphate: NADP+
l-oxidoreductase EC 1.1.1.49) isolated from Paracoccus denitrificans grown on glucose/nitrate exhibits both NAD+-and NADP+-linked activities. Both activities have a pH optimum of pH 9.6 (Glycine/NaOH buffer) and neither demonstrates a Mg2+ requirement. Kinetics for both NAD(P)+ and glucose-6-phosphate were investigated. Phosphoenolpyruvate inhibits both activities in a competitive manner with respect to glucose-6-phosphate. ATP inhibits the NAD+-linked activity competitively with respect to glucose-6-phosphate but has no effect on the NADP+-linked activity. Neither of the two activities are inhibited by 100 M NADH but both are inhibited by NADPH. The NAD+-linked activity is far more sensitive to inhibition by NADPH than the NADP+-linked activity. 相似文献
13.
Sugar beets (Beta vulgaris L. cv. F58-554H1) were cultured hydroponically in growth chambers at 25°C, with a photon flux density of 500 mol m-2s-1. Measurements were made of net CO2 exchange, leaf adenylates (ATP, ADP and AMP), and leaf nicotinamide nucleotides (NAD+, NADP+, NADH, NADPH), over the diurnal period (16h light/8 h dark) and during photosynthetic induction. All the measurements were carried out on recently expanded leaves from 5-week-old plants. When the lights were switched on in the growth chamber, the rate of photosynthetic CO2 uptake, and the levels of leaf ATP and NADPH increased to a maximum in 30 min and remained there throughout the light period. The increase in ATP over the first few minutes of illumination was associated with the phosphorylation of ADP to ATP and the increase in NADPH with the reduction of NADP+; subsequently, the increase in ATP was associated with an increase in total adenylates while the increase in NADPH was associated with an accumulation of NADP+ and NADPH due to the light-driven phosphorylation of NAD+ to NADP+. On return to darkness, ATP and NADPH values decreased much more slowly, requiring 2 to 4 hours to reach minimum values. From these results we suggest that (i) the total adenylate and NADPH and NADP+ (but not NAD+ and NADH) pools increase following exposure to light; (ii) the increase in pool size is not accompanied by any large change in the energy or redox states of the system; and (iii) the measured ratios of ATP/ADP and NADPH/NADP+ for intact leaves are low and constant during steady-state illumination.Abbreviations AEC
adenylate energy charge
- DHAP
dihydroxyacetone phosphate
- MTT
3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide
- PES
phenazine ethosulfate
- PEP
phosphoenolpyruvate
- PGA
3-phosphoglycerate
- PFD
photon flux density
- Ru5P
ribulose-5-phosphate
- Rubisco
ribulose 1,5-bisphosphate carboxylase/oxygenase 相似文献
14.
The activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) from spinach chloroplasts is strongly regulated by the ratio of NADPH/NADP+, with the extent of this regulation controlled by the concentration of ribulose 1,5-diphosphate. Other metabolites of the reductive pentose phosphate cycle are far less effective in mediating the regulation of the enzyme activity by NADPH/NADP+ ratio. With a ratio of NADPH/NADP+ of 2, and a concentration of ribulose 1,5-diphosphate of 0.6 mM, the activity of the enzyme is completely inhibited.This level of ribulose 1,5-diphosphate is well within the concentration range which has been reported for unicellular green algae photosynthesizing in vivo. Ratios of NADPH/NADP+ of 2.0 have been measured for isolated spinach chloroplasts in the light and under physiological conditions.Since ribulose 1,5-diphosphate is a metabolite unique to the reductive pentose phosphate cycle and inhibits glucose-6-phosphate dehydrogenase in the presence of NADPH/NADP+ ratios found in chloroplasts in the light, it is proposed that regulation of the oxidative pentose phosphate cycle is accomplished in vivo by the levels of ribulose 1,5-diphosphate, NADPH, and NADP+.It already has been shown that several key reactions of the reductive pentose phosphate cycle in chloroplasts are regulated by levels of NADPH/NADP+ or other electron-carrying cofactors, and at least one key-regulated step, the carboxylation reaction is strongly affected by 6-phosphogluconate, the metabolite unique to the oxidative pentose phosphate cycle. Thus there is an interesting inverse regulation system in chloroplasts, in which reduced/oxidized coenzymes provide a general regulatory mechanism. The reductive cycle is activated at high NADPH/NADP+ ratios where the oxidative cycle is inhibited, and ribulose 1,5-diphosphate and 6-phosphogluconate provide further control of the cycles, each regulating the cycle in which it is not a metabolite. 相似文献
15.
D Holten D Procsal H L Chang 《Biochemical and biophysical research communications》1976,68(2):436-441
Equilibrium dialysis indicates that rat liver glucose-6-P dehydrogenase binds two molecules of NADP+ per subunit with a dissociation constant of 0.6 × 10?6 M. The NADP+ free enzyme will not bind glucose-6-P indicating a compulsory order of substrate binding. Development of an isotopic assay allowed a direct measurement of the effect of physiological alterations in the NADP+/NADPH ratio on the activity of glucose-6-P and 6-phosphogluconate dehydrogenases. A combination of enzyme induction and altered NADP+/NADPH ratios could produce 30–50 fold changes in the capacity of these enzymes to produce NADPH during alterations in the nutritional state of the animal. 相似文献
16.
A purified and partially characterized novel NADP+-dependent oxidoreductase from Clostridium tyrobutyricum DSM 1460 was applied for the preparative reduction of several 3-oxo acids to (S)-3-hydroxy acids. (R)-3-Hydroxybutyrate was prepared by the same enzyme selectively dehydrogenating the S enantiomer of (R,S)-3-hydroxybutyrate. The enantiomeric purity of the (S)- and (R)-3-hydroxy acids was at least 98% enantiomeric excess (e.e). NADPH for reductions and NADP+ for dehydrogenations were regenerated by applying artificial mediator accepting pyridine nucleotide oxidoreductases in the form of a crude extract of C. thermoaceticum cells. For NADP+ regeneration also the system 2-oxoglutarate/glutamate dehydrogenase was used for comparison. Instead of the purified (S)-3-hydroxycarboxylate oxidoreductase, resting cells of C. tyrobutyricum were also applied for reductions and dehydrogenations with substrate concentrations of 200–400 mM leading to products with e.e. values above 96%.Dedicated to Prof. H.G. Floss on the occasion of his 60th birthday 相似文献
17.
M. Kataoka L. P. S. Rohani K. Yamamoto M. Wada H. Kawabata K. Kita H. Yanase S. Shimizu 《Applied microbiology and biotechnology》1997,48(6):699-703
The asymmetric reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to ethyl (R)-4-chloro-3-hydroxybutanoate (CHBE) using Escherichia coli JM109 (pKAR) cells expressing the aldehyde reductase gene from Sporobolomyces salmonicolor AKU4429 as a catalyst was studied. The reduction required NADP+, glucose and glucose dehydrogenase for NADPH regeneration. In an aqueous system, the substrate was unstable, and inhibition
of the reaction by the substrate was also observed. Efficient conversion of COBE to (R)-CHBE with a satisfactory enantiomeric excess (ee) was attained on incubation with transformant cells in an n-butyl acetate/water two-phase system containing the above NADPH-regeneration system. Under the optimized conditions, with
the periodical addition of COBE, glucose and glucose dehydrogenase, the (R)-CHBE yield reached 1530 mM (255 mg/ml) in the organic phase, with a molar conversion yield of 91.1% and an optical purity
of 91% ee. The calculated turnover of NADP+, based on the amounts of NADP+ added and CHBE formed, was about 5100 mol/mol.
Received: 26 May 1997 / Received revision: 16 July 1997 / Accepted: 29 August 1997 相似文献
18.
NADPH is a specific inhibitor of protein import into glyoxysomes 总被引:2,自引:0,他引:2
Martin R. Pool Eduardo LópezHuertas JimTong Horng Alison Baker 《The Plant journal : for cell and molecular biology》1998,15(1):1-14
We have studied the import of proteins into glyoxysomes in vitro and show that this process is specifically inhibited by NADPH. NADPH affects both binding and translocation of proteins into glyoxysomes, and inhibition is determined by the ratio of NADP+ to NADPH. The site of action of NADPH is most likely within the glyoxysome because (1) pretreatment of glyoxysomes with NADPH, followed by re-isolation of the organelles prior to the import assay, resulted in inhibition of import that could be restored by the addition of NADP+; (2) low concentrations of NADPH inhibited binding of proteins to broken glyoxysome membranes. The sensitivity of protein import to inhibition by NADPH declines as glyoxysomes are converted to leaf-type peroxisomes. A model is proposed that speculates on a possible role for NADPH in regulating protein import into plant peroxisomes. 相似文献
19.
Valentina Bobyleva Nancy Kneer Monica Bellei Daniela Battelli Henry A. Lardy 《Journal of bioenergetics and biomembranes》1993,25(3):313-321
Dehydroepiandrosterone (DHEA) treatment of rats decreases gain of body weight without affecting food intake; simultaneously, the activities of liver malic enzyme and cytosolic glycerol-3-P dehydrogenase are increased. In the present study experiments were conducted to test the possibility that DHEA enhances thermogenesis and decreases metabolic efficiency via trans-hydrogenation of cytosolic NADPH into mitochondrial FADH2 with a consequent loss of energy as heat. The following results provide evidence which supports the proposed hypothesis: (a) the activities of cytosolic enzymes involved in NADPH production (malic enzyme, cytosolic isocitrate dehydrogenase, and aconitase) are increased after DHEA treatment; (b) cytosolic glycerol-3-P dehydrogenase may use both NAD+ and NADP+ as coenzymes; (c) activities of both cytosolic and mitochondrial forms of glycerol-3-P dehydrogenase are increased by DHEA treatment; (d) cytosol obtained from DHEA-treated rats synthesizes more glycerol-3-P during incubation with fructose-1,6-P2 (used as source of dihydroxyacetone phosphate) and NADP+; the addition of citratein vitro further increases this difference; (e) mitochondria prepared from DHEA-treated rats more rapidly consume glycerol-3-P added exogenously or formed endogenously in the cytosol in the presence of fructose-1,6-P2 and NADP+. 相似文献
20.
啤酒酵母的自溶会影响啤酒的风味和品质,对酵母自溶的调控是工业啤酒生产的迫切需求。前期在啤酒酵母自溶的研究中发现柠檬酸循环相关基因对酵母自溶有较大影响。为探究柠檬酸循环中异柠檬酸脱氢酶基因调控对自溶的影响,在典型拉格啤酒酵母(Saccharomyces pastorianus H.)Pilsner中对IDP1和IDP2基因进行了破坏和过表达。结果发现IDP1基因的破坏能提高酵母的抗自溶能力,自溶96 h抗自溶指数为8.40,比原始菌提高了1.5倍。IDP1基因的破坏提高还原型辅酶Ⅱ(nicotinamide adenine dinucleotide phosphate,NADPH)的供应,NADPH/NADP^(+)的比值为1.94,发酵结束时胞内ATP水平比原始菌提高1.8倍,活性氧(reactive oxygen species,ROS)相比原始菌减少10%。IDP2基因的缺失造成酵母快速自溶和NADPH供应的减少,自溶96 h抗自溶指数为4.03,NADPH/NADP^(+)的比值为0.89。发酵结束时胞内ATP水平相比原始菌减少8%,ROS是原始菌的1.3倍。本研究进一步阐释了柠檬酸循环相关基因对酵母自溶的调控机理,为选育自溶性能可控的优良酵母提供了理论基础。 相似文献