Showing papers on "Enzyme assay published in 2006"
TL;DR: Lin et al. as mentioned in this paper identified the Saccharomyces cerevisiae PAH1 (previously known as SMP2) gene that encodes Mg2+dependent PA phosphatase using amino acid sequence information derived from a purified preparation of the enzyme.
515 citations
TL;DR: Rapid diurnal changes in transcript levels are integrated over time to generate quasi-stable changes across large sectors of metabolism, which implies that correlations between metabolites and transcripts are due to regulation of gene expression by metabolites, rather than metabolites being changed as a consequence of a change in gene expression.
Abstract: Background
Genome-wide transcript profiling and analyses of enzyme activities from central carbon and nitrogen metabolism show that transcript levels undergo marked and rapid changes during diurnal cycles and after transfer to darkness, whereas changes in activities are smaller and delayed. In the starchless pgm mutant, where sugars are depleted every night, there are accentuated diurnal changes in transcript levels. Enzyme activities in this mutant do not show larger diurnal changes; instead, they shift towards the levels found in the wild type after several days of darkness. This indicates that enzyme activities change slowly, integrating the changes in transcript levels over several diurnal cycles.
329 citations
TL;DR: It is demonstrated that flavanols either isolated or present in foods could inhibit ACE activity, supported by the association between the consumption of flavanol-rich foods and reductions in blood pressure observed in several experimental models.
Abstract: Angiotensin converting enzyme (ACE) activity was evaluated in the presence of flavanol-rich foods, i.e., wines, chocolates, and teas, and of purified flavonoids. All foods assayed inhibited ACE activity, red wines being more effective than white wine, and green tea more effective than black tea. The inhibition of ACE activity was associated with both phenolic and flavanol content in the foods. When isolated polyphenols were assayed, procyanidins (dimer and hexamer) and epigallocatechin significantly inhibited enzyme activity; similar concentrations of (+)-catechin, (-)-epicatechin, gallic acid, chlorogenic acid, caffeic acid, quercetin, kaempferol, and resveratrol were ineffective. When ACE activity was assayed in rat kidney membranes in the presence of chocolate extracts or purified procyanidins, it was observed that the inhibition depended on the chocolate content of flavanols and the number of flavanol units constituting the procyanidin. These experiments demonstrate that flavanols either isolated or present in foods could inhibit ACE activity. The occurrence of such inhibition in vivo needs to be determined, although is supported by the association between the consumption of flavanol-rich foods and reductions in blood pressure observed in several experimental models.
307 citations
TL;DR: In this paper, rates of enzyme turnover in a volcanic soil with and without added enzymes were determined, and it was shown that adding allophane had a strong positive effect on most enzyme activities.
Abstract: In most ecosystems, the degradation of complex organic material depends on extracellu- lar enzymes produced by microbes. These en- zymes can exist in bound or free form within the soil, but the dynamics of these different enzyme pools remain uncertain. To address this uncer- tainty, I determined rates of enzyme turnover in a volcanic soil with and without added enzymes. I also tested whether or not soil minerals and hu- mic acids would alter enzyme activity. In soils that were gamma-irradiated to stop enzyme produc- tion, 35-70% of the enzyme activity was stable throughout the 21-day incubation. The remaining enzyme fraction decayed at rates ranging from - 0.032 to - 0.628 day -1 . In both the irradiated soils and in soils with added enzymes, addition of the mineral allophane had a strong positive effect on most enzyme activities. Another added mineral, ferrihydrite, had a weak positive effect on some enzymes. Added humic acids strongly inhibited enzyme activity. These findings suggest that minerals, especially allophane, enhance potential enzyme activities in young volcanic soils. How- ever, the actual activity and function of these enzymes may be low under field conditions if stabilization results in less efficient enzyme-sub- strate interactions. If this is the case, then much of the measured enzyme activity in bulk soil may be stabilized but unlikely to contribute greatly to ecosystem processes.
245 citations
TL;DR: In this paper, the cellulolytic enzyme-endoglucanase activity against coir fiber, a major biowaste by bacteria such as Cellulomonas, Bacillus and Micrococcus spp. isolated from coir retting effluents of estuarine environment was studied.
Abstract: The cellulolytic enzyme-endoglucanase activity against coir fibre, a major biowaste by bacteria such as Cellulomonas, Bacillus and Micrococcus spp. isolated from coir retting effluents of estuarine environment was studied. The enzyme assay was carried out by using various concentrations (0.5 − 2%) of substrate of coir powder as a carbohydrate in different pH (5–9) and temperature (20–50 °C). The enzyme activity was minimum in 0.5% substrate concentration at lower pH 5 (0.0087, 0.0143 and 0.0071 U/mL) and at 20 °C temperature (0.0151, 0.0154 and 0.0122 U/mL) by the bacterial strains such as Cellulomonas, Bacillus and Micrococcus spp respectively. Then this level was increased and reached maximum at the neutral pH (0.0172, 0.0165 and 0.0121 U/mL) and at 40 °C (0.0336, 0.0196 and 0.0152 U/mL) by the selected bacterial species. Further increase of pH and temperature, the enzyme activity reduced considerably to 0.0083, 0.0143 and 0.0037 U/mL at pH 9 and 0.0154, 0.0197 and 0.0121 U/mL at 50 °C by the tested bacterial strains. The same trend was also obtained in oth er substrate concentrations such as 1.0, 1.5 and 2.0 %. With in the four substrate concentrations, the endoglucanase enzyme activity was more in 1.5% concentration at the tested pH and temperatures. From the over all result, it was observed that, among the three bacterial strains, the enzyme activity was more in Cellulomonas sp, followed by Bacillus and Micrococcus spp. in varying pH and temperature.
235 citations
TL;DR: The assay format described here is quick, simple, inexpensive, sensitive and accurate, provides a direct measurement of activity and remains the 'gold standard' for the quantification of protein kinase activity.
Abstract: Protein kinase activity results in the incorporation of radiolabeled phosphate from [γ-32P]ATP into a peptide or protein substrate. The measurement of the amount of radioactivity incorporated into a substrate as a function of time and enzyme concentration allows enzyme activity to be quantified. The activity is expressed as a 'unit', where 1 unit corresponds to the amount of protein kinase that catalyzes the incorporation of 1 nanomole of phosphate into the standard substrate in 1 minute. Specific activity is defined as units of activity per milligram protein. The assay format described here is quick, simple, inexpensive, sensitive and accurate, provides a direct measurement of activity and remains the 'gold standard' for the quantification of protein kinase activity. Up to 40 samples can be assayed manually at one time, and the assay takes one person less than 1 hour to complete.
228 citations
TL;DR: Anacardic acids, 6-pentadec(en)ylsalicylic acids isolated from the cashew Anacardium occidentale L. (Anacardiaceae) nut and apple, were found to possess preventive antioxidant activity while salicylic acid did not show this activity.
188 citations
TL;DR: The cell-free extract showed Cr(VI) reducing enzyme activity which was enhanced (>5 fold) by NADH and NADPH and enzyme activity was optimal at pH 6.0 and 30 °C.
Abstract: A Bacillus sp. RE was resistant to chromium and reduced Cr(VI) without accumulating chromium inside the cell. When Cr(VI) was 10 and 40 μg ml−1, >95% of the total Cr(VI) was reduced in 24 and 72 h of growth, respectively, whereas at 80 μg Cr(VI) ml−1 only 50% of Cr(VI) was reduced. However growth was not affected; the cell mass was 0.7–0.8 mg ml−1 in all cases. The cell-free extract showed Cr(VI) reducing enzyme activity which was enhanced (>5 fold) by NADH and NADPH. Like whole cells the enzyme also reduced Cr(VI) with decreasing efficiency on increasing Cr(VI) concentration. The enzyme activity was optimal at pH 6.0 and 30 °C. The enzyme was stable up to 30 °C and from pH 5.5 to 8, but from pH 4 to 5 the enzyme was severely destabilized. Its Km and Vmax were 14 μm and 3.8 nmol min−1 mg−1 respectively. The enzyme activity was enhanced by Cu2+ and Ni2+ and inhibited by Hg2+.
169 citations
TL;DR: Results suggest that arsenic exposure impairs hydrolysis of RNA and proteins in rice seedlings due to inhibition of RNase and proteases activities and that proline accumulating under As3+ toxicity appears to serve as enzyme protectant.
162 citations
TL;DR: In this paper, Salicylic acid (SA), a likely signal in the response of plants to stress, and phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), a key enzyme in phenylpropanoid metabolism, perform defenserelated functions within plants.
159 citations
TL;DR: The fluorescent assay for angiotensin-I converting enzyme was adequate for the study of ACE inhibition by captopril and several peptides and it also showed a very good correlation with a well-established method.
TL;DR: Interindividual variability of antioxidant enzyme activity in healthy young adults was partially explained by significant associations with three known genetic polymorphisms, and was further modified by gender and ethnicity.
Abstract: ObjectivesThis study examined the association between genetic polymorphisms and enzyme activity for antioxidant enzymes that share a common detoxification pathway: manganese superoxide dismutase (MnSOD), glutathione peroxidase-1 (GPX1) and catalase.MethodsMnSOD, GPX1, and catalase activities were me
TL;DR: The enzyme had a high degrading activity for the Bβ-chains and Aα-chain of fibrin(ogen), and also acted on thrombotic and fibrinolytic factors of blood, such as plasminogen, urokinase, thrombin, and kallikrein.
Abstract: Bacillus subtilis DC33 producing a novel fibrinolytic enzyme was isolated from Ba-bao Douchi, a traditional soybean-fermented food in China. The strong fibrin-specific enzyme subtilisin FS33 was purified to electrophoretic homogeneity using the combination of various chromatographic steps. The optimum temperature, pH value, and pI of subtilisin FS33 were 55°C, 8.0, and 8.7, respectively. The molecular weight was 30 kDa measured by SDS–PAGE under both reducing and non-reducing conditions. The enzyme showed a level of fibrinolytic activity that was about six times higher than that of subtilisin Carlsberg. The first 15 amino acid residues of N-terminal sequence of the enzyme were A-Q-S-V-P-Y-G-I-P-Q-I-K-A-P-A, which are different from that of other known fibrinolytic enzymes. The amidolytic activities of subtilisin FS33 were inhibited completely by 5 mM phenylmethanesulfonyl fluoride (PMSF) and 1 mM soybean trypsin inhibitor (SBTI), but 1,4-dithiothreitol (DTT), β-mercaptoethanol, and p-hydroxymercuribenzoate (PHMB) did not affect the enzyme activity; serine and tryptophan are thus essential in the active site of the enzyme. The highest affinity of subtilisin FS33 was towards N-Succ-Ala-Ala-Pro-Phe-pNA. Therefore, the enzyme was considered to be a subtilisin-like serine protease. The fibrinolytic enzyme had a high degrading activity for the Bβ-chains and Aα-chain of fibrin(ogen), and also acted on thrombotic and fibrinolytic factors of blood, such as plasminogen, urokinase, thrombin, and kallikrein. So subtilisin FS33 was able to degrade fibrin clots in two ways, i.e., (a) by forming active plasmin from plasminogen and (b) by direct fibrinolysis.
TL;DR: Results indicate that Triapine-induced inhibition of ribonucleotide reductase is caused by ROS, and suggest that ROS may ultimately be responsible for the pharmacologic effects of TriAPine in vivo.
Abstract: Ribonucleotide reductase plays a central role in cell proliferation by supplying deoxyribonucleotide precursors for DNA synthesis and repair. The holoenzyme is a protein tetramer that features two large (hRRM1) and two small (hRRM2 or p53R2) subunits. The small subunit contains a di-iron cluster/tyrosyl radical cofactor that is essential for enzyme activity. Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone, 3-AP) is a new, potent ribonucleotide reductase inhibitor currently in phase II clinical trials for cancer chemotherapy. Ferric chloride readily reacts with Triapine to form an Fe(III)-(3-AP) complex, which is reduced to Fe(II)-(3-AP) by DTT. Spin-trapping experiments with 5,5-dimethyl-1-pyrroline- N -oxide prove that Fe(II)-(3-AP) reduces O2 to give oxygen reactive species (ROS). In vitro activity assays show that Fe(II)-(3-AP) is a much more potent inhibitor of hRRM2/hRRM1 and p53R2/hRRM1 than Triapine. Electron paramagnetic resonance measurements on frozen solutions of hRRM2 and p53R2 show that their tyrosyl radicals are completely quenched by incubation with Fe(II)-(3-AP). However, the enzyme activity is maintained in protein samples supplemented with catalase alone or in combination with superoxide dismutase. Furthermore, catalase alone or in combination with superoxide dismutase markedly decreases the antiproliferative effect of Triapine in cytotoxicity assays. These results indicate that Triapine-induced inhibition of ribonucleotide reductase is caused by ROS. We suggest that ROS may ultimately be responsible for the pharmacologic effects of Triapine in vivo . [Mol Cancer Ther 2006;5(3):586–92]
TL;DR: A thermostable, alkaline active xylanase was purified to homogeneity from the culture supernatant of an alkaliphilic Bacillus halodurans S7, which was isolated from a soda lake in the Ethiopian Rift Valley and degraded xylan in an endo-fashion.
TL;DR: Measurements of brain 3HA0 indicate that measurements of brain may yield significant information concerning a possible role of quinolinic acid in brain function and/or dysfunction.
Abstract: In mammalian peripheral organs, 3-hydroxyanthranilic acid oxygenase (3HAO), catalyzing the conversion of 3-hydroxyanthranilic acid to quinolinic acid, constitutes a link in the catabolic pathway of tryptophan to NAD Because of the possible involvement of quinolinic acid in the initiation of neurodegenerative phenomena, we examined the presence and characteristics of 3HAO in rat brain tissue A simple and sensitive assay method, based on the use of [carboxy-14C]3-hydroxyanthranilic acid as a substrate, was developed and the enzymatic product, [14C]quinolinic acid, identified by chromatographic and biochemical means Kinetic analysis of rat forebrain 3HAO revealed a Km of 36 +/- 05 microM for 3-hydroxyanthranilic acid and a Vmax of 737 +/- 95 pmol quinolinic acid/h/mg tissue The enzyme showed pronounced selectivity for its substrate, since several substances structurally and metabolically related to 3-hydroxyanthranilic acid caused less than 25% inhibition of activity at 500 microM Both the Fe2+ dependency and the distinct subcellular distribution (soluble fraction) of brain 3HAO indicated a close resemblance to 3HAO from peripheral tissues Examination of the regional distribution in the brain demonstrated a 10-fold variation between the region of highest (olfactory bulb) and lowest (retina) 3HAO activity The brain enzyme was present at the earliest age tested (7 days postnatum) and increased to 167% at 15 days before reaching adult levels Enzyme activity was stable over extended periods of storage at -80 degrees C Taken together, these data indicate that measurements of brain 3HAO may yield significant information concerning a possible role of quinolinic acid in brain function and/or dysfunction
TL;DR: Intact synaptosomes isolated from mammalian brain tissues (rat, mouse, gerbil, and human) have an ATP hydrolyzing enzyme activity on their external surface that possesses characteristics consistent with those that have been described for ecto‐ATPases of various other cell types.
Abstract: Intact synaptosomes isolated from mammalian brain tissues (rat, mouse, gerbil, and human) have an ATP hydrolyzing enzyme activity on their external surface. The synaptosomal ecto-ATPase(s) possesses characteristics consistent with those that have been described for ecto-ATPases of various other cell types. The enzyme has a high affinity for ATP (the apparent Km values are in the range of 2-5 X 10(-5) M), and is apparently stimulated equally well by either Mg2+ or Ca2+ in the absence of any other cations. The apparent activation constant for both divalent cations is approximately 4 X 10(-4) M in all mammalian brain tissues studied. The involvement of a non-specific phosphatase in the hydrolysis of externally added ATP is excluded. ATP hydrolysis is maximal in the pH range 7.4-7.8 for both divalent cation-dependent ATPase activities. Dicyclohexylcarbodiimide, 2,4-dinitrophenol, trifluoperazine, chlorpromazine, and p-chloromercuribenzoate (50 microM) inhibit the ecto-ATPase, whereas ouabain (1 mM) and oligomycin (3.5 micrograms X mg-1 protein) show little or no inhibition of this enzyme activity. Inhibitor data suggest that the Mg2+- and Ca2+-dependent ecto-ATPase may represent two different enzymes on the surface of synaptosomes.
TL;DR: The inhibitory profile of PfNDH2 revealed that the enzyme activity was insensitive to rotenone, consistent with recent genomic data indicating the absence of the canonical NADH:dehydrogenase enzyme, and proof-of-concept experiments revealing that targeting the ETC's Q-cycle by inhibition of both Pf NDH2 and the bc1 complex is highly synergistic.
Abstract: This study reports on the first characterization of the alternative NADH:dehydrogenase (also known as alternative complex I or type II NADH:dehydrogenase) of the human malaria parasite Plasmodium falciparum, known as PfNDH2. PfNDH2 was shown to actively oxidize NADH in the presence of quinone electron acceptors CoQ, and decylubiquinone with an apparent K-m for NADH of approximately 17 and 5 IxM, respectively. The inhibitory profile of PfNDH2 revealed that the enzyme activity was insensitive to rotenone, consistent with recent genomic data indicating the absence of the canonical NADH:dehydrogenase enzyme. PfNDH2 activity was sensitive to diphenylene iodonium chloride and diphenyl iodonium chloride, known inhibitors of alternative NADH:dehydrogenases. Spatiotemporal confocal imaging of parasite mitochondria revealed that loss of PfNDH2 function provoked a collapse of mitochondrial transmembrane potential (Psi(m)), leading to parasite death. As with other alternative NADH:dehydrogenases, PfNDH2 lacks transmembrane domains in its protein structure, and therefore, it is proposed that this enzyme is not directly involved in mitochondrial transmembrane proton pumping. Rather, the enzyme provides reducing equivalents for downstream proton-pumping enzyme complexes. As inhibition of PfNDH2 leads to a depolarization of mitochondrial Psi(m), this enzyme is likely to be a critical component of the electron transport chain (ETC). This notion is further supported by proof-of-concept experiments revealing that targeting the ETC's Q-cycle by inhibition of both PfNDH2 and the bc(1), complex is highly synergistic. The potential of targeting PfNDH2 as a chemotherapeutic strategy for drug development is discussed.
TL;DR: Reflectance measurements during wash performance studies show that the purification and characterization of a single salt, solvent, detergent and bleach tolerant alkaline serine protease produced by a truly marine bacterium is capable of almost complete removal of recalcitrant blood and egg stains in both wet and dry wash operations.
TL;DR: In thermostability experiments, the enzyme followed first-order kinetics of thermal inactivation, and the half-lives of the enzyme at 75, 80, 85, 90, and 95 °C were 91, 48, 35, 2.6, and 0.72 h, respectively, suggesting that the enzyme is highly stable up to 85-°C.
TL;DR: Enzyme assay on dried-blood filter paper is a suitable method to screen for several lysosomal storage diseases despite the low individual incidence of these pathologies, and the incorporation of individual enzyme assays in neonatal screening programs could be justified toScreen for diseases with relatively high local frequency and therapeutic measures available.
TL;DR: Some important aspects of cyanobacterial hepatotoxins and methods of analysis for these toxins are reviewed.
TL;DR: Resveratrol pharmacological dosage inhibited aromatase at both the enzyme and mRNA levels, and Luciferase reporter gene assays revealed that resver atrol could repress the transcriptional control dictated by the promoter regulation.
Journal Article•
TL;DR: In this paper, a-amylase enzyme activity was observed at 55 °C and pH=5. At 75 °C, enzyme showed 90 % activity compared to 55°C.
Abstract: Summary Production of a-amylase under solid-state fermentation by Bacillus cereus MTCC 1305 has been investigated using wheat bran and rice flake manufacturing waste as substrates. With wheat bran, highest enzyme production expressed as units per mass of dry substrate ((94±2) U/g) was observed. Production parameters were optimized as inoculum size 10 % (volume per mass) and substrate:moisture ratio 1:1. Among different carbon sources supplemented, glucose (0.04 g/g) showed enhanced enzyme production ((122±5) U/g). Supplementation of different nitrogen sources (0.02 g/g) showed decline in enzyme production. Optimum a-amylase enzyme activity was observed at 55 °C and pH=5. At 75 °C, enzyme showed 90 % activity compared to 55 °C.
TL;DR: The N-terminal sequence of the purified enzyme showed a significant homology with the family 1 β-glucosidases of Trichoderma reesei and Humicola isolens even though these two enzymes are much smaller in size.
TL;DR: In this paper, the effect of different commercial detergents and surfactants on enzymatic activity of lipase from Fusarium oxysporum was observed through p-nitrophenylpalmitate (pNPP) assay.
TL;DR: It was interesting to note that at higher pH such as 9, 10 and 11 the enzyme activity increased over the period of incubation, which makes this enzyme potentially very effective for industrial applications.
TL;DR: The present investigation deals with purification and thermal characterization of an acid invertase produced by Fusarium solani in submerged culture, and the effects of alpha-chymotrypsin and 4 M urea were tetraphasic with periodic gain and loss of enzyme activity.
Abstract: The present investigation deals with purification and thermal characterization of an acid invertase produced by Fusarium solani in submerged culture. The maximum enzyme activity (9.90 U mL(-1)) was achieved after 96 h of cultivation at pH 5.0 and 30 degrees C in a basal medium containing molasses (2%) as the carbon and energy source supplemented with 1% peptone. Invertase was purified by ammonium sulfate fractionation and column chromatography on DEAE-cellulose and Sephadex G-200. The purified enzyme was proven to be homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular mass of the enzyme was 65 kDa. The optimum pH and temperature for activity were 2.6 and 50 degrees C, respectively. The Km value for sucrose was 3.57 mM with an activation energy of 4.056 kJ mol(-1). Enthalpies of activation (DeltaH) were decreased while entropies (DeltaS) of activation increased at higher temperatures. The effects of alpha-chymotrypsin and 4 M urea were tetraphasic with periodic gain and loss of enzyme activity. A possible explanation for the thermal inactivation of invertase at higher temperatures is also discussed.
TL;DR: In this paper, an endolytic cysteine protease (EC3.4.22.2) from Carica papaya latex has been chemically modified using different dicarboxylic anhydrides of citraconic, phthalic, maleic and succinic acids.
Abstract: Chemical modification is a useful method to recognize and modify functional determinants of enzymes. Papain, an endolytic cysteine protease (EC3.4.22.2) from Carica papaya latex has been chemically modified using different dicarboxylic anhydrides of citraconic, phthalic, maleic and succinic acids. These anhydrides reacted with five to six amino groups of the lysine residues in the enzyme, thereby changing the net charge of the enzyme from positive to negative. The resultant enzyme had its optimum pH shifted from 7 to 9 and change in temperature optima from 60 to 80 °C. The modified papain also had a higher thermostability. Stability of the modified papain was further increased by immobilization of the enzyme either by adsorption onto inert matrix or by entrapment in polysaccharide polymeric gels. Entrapment in starch gel showed better retention of enzyme activity. Incorporation of modified and immobilized enzymes to branded domestic detergent powders was found to have very good activity retention. The papain entrapped in starch gel showed better stability and activity retention than in other carbohydrate polymers when added to domestic detergent powders.
TL;DR: It is demonstrated that cadmium decreases the content of Zn2+, changes the conformation of Cu,Zn‐SOD protein to decrease its enzyme activity, and causes oxidative stress‐induced neural cell apoptosis.
Abstract: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder disease. Ten percent of the ALS patients are congenital (familial ALS), and the other 90% are sporadic ALS (SALS). It has been shown that mutations found in the Cu,Zn-SOD cause 20% of the familial ALS due to its low enzyme activity. We hypothesized that heavy metals may interfere the structure of Cu,Zn-SOD protein to suppress its activity in some of the SALS. In this study, we expressed and characterized the recombinant human Cu,Zn-SOD under various concentrations of Cu(2+), Zn(2+), and Cd(2+). By atomic absorption spectrophotometry, we demonstrated that adding of cadmium significantly increased the content of cadmium ion, but reduced its Zn(2+) content and enzyme activity of the Cu,Zn-SOD protein. The data of circular dichroism spectra demonstrated that the secondary structure of Cu,Zn-SOD/Cd is different from Cu,Zn-SOD, but close to apo-SOD. In addition to the effect of cadmium on Cu,Zn-SOD, cadmium was also shown to induce neural cell apoptosis. To further investigate the mechanism of neural cell apoptosis induced by cadmium, we used proteomics to analyze the altered protein expressions in neural cells treated with cadmium. The altered proteins include cellular structural proteins, stress-related and chaperone proteins, proteins involved in reactive oxygen species (ROS), enzyme proteins, and proteins that mediated cell death and survival signaling. Taken together, in this paper, we demonstrate that cadmium decreases the content of Zn(2+), changes the conformation of Cu,Zn-SOD protein to decrease its enzyme activity, and causes oxidative stress-induced neural cell apoptosis.