Inhibition Of Acid Phosphatase Research Articles

Colorimetric and photothermal dual-mode sensing platform for point-of-care testing of acid phosphatase activity and inhibitor screening based on oxidase-mimetic activity of Pt-Ni alloy nanoparticles

Colorimetric and photothermal dual-mode sensing platform for point-of-care testing of acid phosphatase activity and inhibitor screening based on oxidase-mimetic activity of Pt-Ni alloy nanoparticles

Persistent PKA activation redistributes NaV1.5 to the cell surface of adult rat ventricular myocytes.

During chronic stress, persistent activation of cAMP-dependent protein kinase (PKA) occurs, which can contribute to protective or maladaptive changes in the heart. We sought to understand the effect of persistent PKA activation on NaV1.5 channel distribution and function in cardiomyocytes using adult rat ventricular myocytes as the main model. PKA activation with 8CPT-cAMP and okadaic acid (phosphatase inhibitor) caused an increase in Na+ current amplitude without altering the total NaV1.5 protein level, suggesting a redistribution of NaV1.5 to the myocytes' surface. Biotinylation experiments in HEK293 cells showed that inhibiting protein trafficking from intracellular compartments to the plasma membrane prevented the PKA-induced increase in cell surface NaV1.5. Additionally, PKA activation induced a time-dependent increase in microtubule plus-end binding protein 1 (EB1) and clustering of EB1 at myocytes' peripheral surface and intercalated discs (ICDs). This was accompanied by a decrease in stable interfibrillar microtubules but an increase in dynamic microtubules along the myocyte surface. Imaging and coimmunoprecipitation experiments revealed that NaV1.5 interacted with EB1 and β-tubulin, and both interactions were enhanced by PKA activation. We propose that persistent PKA activation promotes NaV1.5 trafficking to the peripheral surface of myocytes and ICDs by providing dynamic microtubule tracks and enhanced guidance by EB1. Our proposal is consistent with an increase in the correlative distribution of NaV1.5, EB1, and β-tubulin at these subcellular domains in PKA-activated myocytes. Our study suggests that persistent PKA activation, at least during the initial phase, can protect impulse propagation in a chronically stressed heart by increasing NaV1.5 at ICDs.

Phosphorescence, fluorescence, and colorimetric triple-mode sensor for the detection of acid phosphatase and corresponding inhibitor

Acid phosphatase (ACP) as a clinical diagnostic biomarker for several pathophysiological diseases has aroused widespread interest. Compared to commonly developed single-mode ACP detection technology, the multi-mode detection method with self-validation can provide more reliable results. Herein, we proposed a triple-mode phosphorescence, fluorescence, and colorimetric method for ACP detection in combination with CDs@SiO2. HAuCl4 with oxidase-like activity can catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to the blue oxide TMB (TMBox), offering absorption signals and quenching the phosphorescence and fluorescence of CDs@SiO2 based on the internal filtration effect (IFE). ACP can hydrolyze ascorbic acid 2-phosphate (AAP) to yield ascorbic acid (AA), thereby reducing TMBox to TMB, triggering solution fading and restoring phosphorescence and fluorescence signals. When the ACP inhibitor malathion is present, the reduction of TMBox is hindered, which successively led to the suppression of CDs@SiO2 phosphorescence and fluorescence signal recovery. According to these principles, triple-mode ACP (LOD = 0.0026 mU mL−1) and malathion detections (LOD = 0.039 μg mL−1) with favorable accuracy and sensitivity are realized. With simplicity, robustness, and versatility, the triple-mode sensor can be extended to the detection of the AAP hydrolase family and the screening of corresponding inhibitors.

Oxidase-like Fe–N/C single atom nanozyme enables sensitive detection of ascorbic acid and acid phosphatase

The development of cost-effective and easy-to-use strategies for the detection of ascorbic acid (AA) and acid phosphatase (ACP) is in high demand but challenging. Thus, we report a novel colorimetric platform based on Fe–N/C single atom nanozyme with efficient oxidase mimicking activity for their highly sensitive detection. The designed Fe–N/C single atom nanozyme can directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue oxidation product (oxTMB) in the absence of H2O2. In addition, L-ascorbic acid 2-phosphate can be hydrolyzed to ascorbic acid in the presence of ACP, which inhibits the oxidation reaction and results in a significant bleaching of the blue color. Based on these phenomena, a novel colorimetric assay with high catalytic activity was developed for the determination of ascorbic acid and acid phosphatase with detection limits of 0.092 μM and 0.048 U/L, respectively. Notably, this strategy was successfully applied to the determination of ACP in human serum samples and evaluate ACP inhibitors, indicating its potential as a valuable tool for clinical diagnosis and research.

Optimization of an α-aminonaphthylmethylphosphonic acid inhibitor of purple acid phosphatase using rational structure-based design approaches

Purple acid phosphatases (PAPs) are ubiquitous binuclear metallohydrolases that have been isolated from various animals, plants and some types of fungi. In humans and mice, elevated PAP activity in osteoclasts is associated with osteoporosis, making human PAP an attractive target for the development of anti-osteoporotic drugs. Based on previous studies focusing on phosphonate scaffolds, as well as a new crystal structure of a PAP in complex with a derivative of a previously synthesized α-aminonaphthylmethylphosphonic acid, phosphonates 24–40 were designed as new PAP inhibitor candidates. Subsequent docking studies predicted that all of these compounds are likely to interact strongly with the active site of human PAP and most are likely to interact strongly with the active site of pig PAP. The seventeen candidates were synthesized with good yields and nine of them (26–28, 30, 33–36 and 38) inhibit in the sub-micromolar to nanomolar range against pig PAP, with 28 and 35 being the most potent mammalian PAP inhibitors reported with Ki values of 168 nM and 186 nM, respectively. This study thus paves the way for the next stage of drug development for phosphonate inhibitors of PAPs as anti-osteoporotic agents.

Insights into the interaction mechanism of acid phosphatase from Lateolabrax japonicus livers and rosmarinic acid using multispectroscopy and molecular docking

Acid phosphatase (ACP) is a key enzyme that hydrolyzes inosinic acid. The mechanisms underlying the interaction between rosmarinic acid (RA) and ACP and the inhibition of the enzyme were investigated using inhibition kinetics, UV–visible and fluorescence spectroscopy, circular dichroism, and molecular docking. The results showed that RA was a reversible inhibitor of ACP and that the inhibition mechanism was uncompetitive. The ACP fluorescence was quenched by RA, and the quenching mode was static. The interaction of ACP with RA was driven by H bonds and van der Waals forces. The addition of RA increased the α-helix content and decreased the β-sheet, β-turn, and random coil contents in ACP, thereby altering the secondary structure of the enzyme. This study enriched our understanding of inhibitory and interaction mechanisms involving ACP and RA.

MXene-derived Ti3C2 quantum dots-based ratiometric fluorescence probe for ascorbic acid and acid phosphatase determination

As a burgeoning zero-dimensional nanomaterial, MXene quantum dots which are derived from two-dimensional transition-metal carbides have attracted a lot of interest lately. The transformation of two-dimensional MXene into zero-dimensional structures of a few nanometers enables these recently discovered materials to possess an exceptional quantum size effect and remarkable photoluminescence characteristics. Hence, we synthesized N doped Ti3C2 MXene quantum dots (N-Ti3C2 MQDs) exhibiting bright blue fluorescence through small-molecule amine-assisted solvothermal strategy. In this work, we constructed a novel ratiometric fluorescence biosensor for the determination of ascorbic acid (AA) and acid phosphatase (ACP) based on the excellent optical performance of N-Ti3C2 MQDs and combined o-phenylenediamine (OPD). This ratiometric strategy was established based on the inner filter effect between N-Ti3C2 MQDs and the oxide of OPD. Sensitive fluorometric analyses of AA and ACP were achieved successfully in the respective ranges of 2–240 μM and 0.15–3.75 U/L with respective limits of detection down to 0.82 μM and 0.02 U/L. Moreover, the response time of this fluorescence sensor for AA and ACP determination was less than 1.5 h. The intraday and interday relative standard deviations for AA and ACP assay were all below 8.3 %, suggesting the good reproducibility of this sensor. In addition, the profuse color changed under UV light with analytes concentrations increased and exhibited great potential for visual detection and on-site application. The proposed method was further utilized to screen of potential ACP inhibitors, indicating that this probe has great potential in clinical practice.

Optimalisation of the Activation Medium and Effect of Inhibiting Activities of Acid Phosphatase, Lactate Dehydrogenase and β-N-Acetylglucosaminidase on the Fertilisation Success of Eurasian Perch (Perca fluviatilis L.).

Simple SummaryThe purpose of this study is to determine the composition of the optimal activating solution for activating sperm motility and perch eggs, because scientific studies and reproductive procedures should be conducted in stable and repeatable conditions. We found that the best activating solution was composed of 80 mM NaCl, 20 mM KCl, 10 mM Tris, with pH 8.0 and 206 mOsm/kg. In spite of this, we also checked the influence of adding the enzyme inhibitors, such as ammonium molybdate–acid phosphatase inhibitor, gossypol – lactate dehydrogenase inhibitor and acetamide–β-N-acetylglucosaminidase inhibitor on perch sperm motility and successful perch fertilisation. We showed that the addition of acid phosphatase inhibitor in perch semen did not affect the process of fertilisation; in contrast, the addition of lactate dehydrogenase and β-N-acetylglucosaminidase inhibitors significantly decreased the percentage of perch fertilised eggs.Although methods for the artificial reproduction of perch have been developed, a lack of information remains regarding the enzymes present in its semen, as well as their role in the fertilisation process. In this study, we first select the optimal activating solution for perch fertilisation and then determine the inhibition effect of enzymes that have already been reported as present in the sperm of teleosts—acid phosphatase (AcP), lactic dehydrogenase (LDH) and β-N-acetylglucosaminidase (β-NAGase)—on the percentage of motile spermatozoa and fertilised eggs. Of the 8 studied activation media, a solution composed of 80 mM NaCl, 20 mM KCl, 10 mM Tris, with pH 8.0 and 206 mOsm/kg proved to be optimal for perch gametes. The addition of ammonium molybdate (AcP inhibitor) caused no significant reduction in the percentage of fertilised eggs. On the other hand, the addition of 0.25 mM gossypol (LDH inhibitor) and 0.125 M acetamide (β-N-acetylglucosaminidase inhibitor) significantly decreased the fertilisation percentage to 41.1% and 52.4%, respectively, in contrast to the control (89.9 %). Both LDH and β-NAGase thus seem to play a very important role in the perch fertilisation process.

Kinetic Studies of Newly Patented Aminoalkanol Derivatives with Potential Anticancer Activity as Competitive Inhibitors of Prostate Acid Phosphatase.

Background: Acid phosphatase and its regulation are important objects of biological and clinical research and play an important role in the development and treatment of prostate and bone diseases. The newly patented aminoalkanol (4-[2-hydroxy-3-(propan-2-ylamino)propyl]-1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione hydrochloride) (I) and (4-[3-(dimethylamino)-2-hydroxypropyl]-1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione hydrochloride) (II) derivatives have potential anticancer activity, and their influence on enzymatic activity can significantly impact the therapeutic effects of acid phosphatase against many diseases. Therefore, in this study, we investigated the action of compounds (I) and (II) on acid phosphatase. Methods: Capillary electrophoresis was used to evaluate the inhibition of acid phosphatase. Lineweaver–Burk plots were constructed to compare the Km of this enzyme in the presence of inhibitors (I) or (II) with the Km in solutions without these inhibitors. Results: Compound (I) showed a stronger competitive inhibition against acid phosphatase, whereas derivative (II) showed a weaker competitive type of inhibition. The detailed kinetic studies of these compounds showed that their type and strength of inhibition as well as affinity depend on the kind of substituent occurring in the main chemical molecule. Conclusions: This study is of great importance because the disclosed inhibition of acid phosphatase by compounds (I) and (II) raises the question of whether these compounds could have any effect on the treatment possibilities of prostate diseases.

The in vivo disposition of subcutaneous injected 14C-razuprotafib (14C-AKB-9778), a sulphamic acid phosphatase inhibitor, in nonclinical species and human

The disposition of radioactivity following subcutaneous 14C-razuprotafib, a Tie2 activator, was explored in multiple species. The absorption and clearance of razuprotafib and total radioactivity in human plasma are rapid and pharmacokinetics support razuprotafib as primary circulating component. Radioactivity is distributed greater to human plasma than whole blood (B:P = 0.36). In pigmented rats, radioactivity distributes to whole-body tissues rapidly and, within 24 h, is localised to elimination pathway end organs and injection site. Overall recovery of radioactivity across species is >93%, with the majority recovered within 24–48 h, and >80% in faeces. The CYP2C8 enzyme contributes significantly to razuprotafib metabolism. A hydrolysis product of razuprotafib (m/z− 380) is the main component in rat plasma at 2 h (49% peak area radioactivity), while razuprotafib (m/z− 585) is the main component in plasma for dog (58%), monkey (99.3%), and human (100%). Razuprotafib is present in dog, monkey, and human faeces, with the greatest percentage of radioactivity as metabolites. The major metabolite (>25%) in monkey and human, m/z− 633, is an S-methylated oxidised derivative of razuprotafib and is localised in faeces. Overall disposition of 14C-razuprotafib in human is best modelled by monkey over lower order species.

Oxidative metabolism of razuprotafib (AKB-9778), a sulfamic acid phosphatase inhibitor, in human microsomes and recombinant human CYP2C8 enzyme

Razuprotafib, a sulphamic acid-containing phosphatase inhibitor, is shown in vivo to undergo enzymatic oxidation and methylation to form a major metabolite in monkey and human excreta with an m/z – value of 633. LC-MS/MS analysis of samples derived from incubations of razuprotafib with human liver microsomes and recombinant CYP2C8 enzyme has elucidated the metabolic pathway for formation of the thiol precursor to the S-methyl metabolite MS633 (m/z – 633). Under in vitro conditions, the major pathway of razuprotafib metabolism involves extensive oxidation of the thiophene and phenyl rings. A single oxidation takes place at one of the phenyl groups. Multiple oxidations occur at the thiophene moiety: initial oxidation results in the formation of a thiolactone followed by a second oxidation giving rise to an S-oxide of the thiolactone, which is further metabolised to the ring-opened form and ultimate formation of a thiol (m/z – 619). An additional mono-oxidation pathway involves epoxidation of the thiophene followed by hydrolysis to a diol. The thiol and diol metabolites are trapped by the addition of a nucleophilic trapping agent, 3-methoxyphenacyl bromide (MPB), giving adducts with m/z – 767. The thiol is a likely precursor to the major in vivo razuprotafib metabolite, MS633.

Biochemical characterization of a recombinant acid phosphatase from Acinetobacter baumannii.

Genomic sequence analysis of Acinetobacter baumannii revealed the presence of a putative Acid Phosphatase (AcpA; EC 3.1.3.2). A plasmid construct was made, and recombinant protein (rAcpA) was expressed in E. coli. PAGE analysis (carried out under denaturing/reducing conditions) of nickel-affinity purified protein revealed the presence of a near-homogeneous band of approximately 37 kDa. The identity of the 37 kDa species was verified as rAcpA by proteomic analysis with a molecular mass of 34.6 kDa from the deduced sequence. The dependence of substrate hydrolysis on pH was broad with an optimum observed at 6.0. Kinetic analysis revealed relatively high affinity for PNPP (Km = 90 μM) with Vmax, kcat, and Kcat/Km values of 19.2 pmoles s-1, 4.80 s-1(calculated on the basis of 37 kDa), and 5.30 x 104 M-1s-1, respectively. Sensitivity to a variety of reagents, i.e., detergents, reducing, and chelating agents as well as classic acid phosphatase inhibitors was examined in addition to assessment of hydrolysis of a number of phosphorylated compounds. Removal of phosphate from different phosphorylated compounds is supportive of broad, i.e., ‘nonspecific’ substrate specificity; although, the enzyme appears to prefer phosphotyrosine and/or peptides containing phosphotyrosine in comparison to serine and threonine. Examination of the primary sequence indicated the absence of signature sequences characteristic of Type A, B, and C nonspecific bacterial acid phosphatases.

Colorimetric determination of acid phosphatase activity and inhibitor screening based on in situ polymerization of aniline catalyzed by gold nanoparticles.

A colorimetric assay for acid phosphatase (ACP) was constructed that isbased on in situ polymerization of aniline catalyzed by gold nanoparticles (AuNPs). Aniline can be polymerized by ammonium persulfate (APS) in acidic condition and form gold-polyaniline core-shell nanoparticles (Au@PANI NPs) in the presence of AuNPs with the assistance of sodium dodecyl sulfate (SDS). AuNPs were also found to accelerate the polymerization process of aniline and thus shorten the reaction time. Upon the introduction of ascorbic acid (AA), the oxidant APS was consumed via the redox reaction. That led to the suppression of the formation of PANI. Consequently, ACP activity can be supervised on the basis of hydrolysis of 2-phospho-L-ascorbic acid trisodium salt (AAP) catalyzed by ACP to release AA. With the increase of ACP activity, the intensity ratio of the absorbance at λ705 nm (A705) and the absorbance at λ530 nm (A530) gradually decreased and the color gradually changed from dark-green to light-green to blue-gray to purple and eventually to pink. This method for ACP determination worked in the range 0.40 to 2.00U·L-1. The detection limit is 0.043U·L-1. The assay was applied to determine ACP in human serum. The recovery ranged from 81.0 to 104.6%. Relative standard deviation was less than 5%. This suits the request forbiological sample analysis. Graphical abstract Schematic presentation of the colorimetric determination of acid phosphatase activity and inhibitor screening based on in situ polymerization of aniline catalyzed by gold nanoparticles. : acid phosphatase (ACP); : gold nanoparticles (AuNPs); : gold-polyaniline core-shell nanoparticles (Au@PANI NPs); ascorbic acid (AA); 2-phospho-L-ascorbic acid trisodium salt (AAP).

Synthesis of illudalic acid and analogous phosphatase inhibitors.

Developing an efficient, concise synthesis of the fungal natural product illudalic acid has been a long-standing challenge, made more pressing by the recent discovery that illudalic acid and analogs are selective phosphatase inhibitors. Syntheses of illudalic acid have become progressively more efficient over the decades yet remain strategically grounded in a 17-step synthesis reported in 1977. Here we validate a two-step process-convergent [4 + 2] benzannulation and one-pot coordinated functional group manipulations-for preparing the key trifunctional pharmacophore of illudalic acid. The modular building blocks are readily available in 2-3 steps, for a longest linear sequence (LLS) of 5 steps to illudalic acid from 3,3-dimethylcyclopentanone. A small collection of analogous indanes and tetralins featuring the same pharmacophore were prepared by a similar route. These compounds potently and selectively inhibit the human leukocyte common antigen-related (LAR) subfamily of protein tyrosine phosphatases (PTPs). Evidence supporting a postulated covalent ligation mechanism is provided herein.

Ectophosphatase activity in the triple-negative breast cancer cell line MDA-MB-231.

Breast cancer is one of the most common cancers in the female population worldwide, and its development is thought to be associated with genetic mutations that lead to uncontrolled and accelerated growth of breast cells. This abnormal behavior requires extra energy, and indeed, tumor cells display a rewired energy metabolism compared to normal breast cells. Inorganic phosphate (Pi) is a glycolytic substrate of glyceraldehyde-3-phosphate dehydrogenase and has an important role in cancer cell proliferation. For cells to obtain Pi, ectoenzymes in the plasma membrane with their catalytic site facing the extracellular environment can hydrolyze phosphorylated molecules, and this is an initial and possibly limiting step for the uptake of Pi by carriers that behave as adjuvants in the process of energy harvesting and thus partially contributes to tumor energy requirements. In this study, the activity of an ectophosphatase in MDA-MB-231 cells was biochemically characterized, and the results showed that the activity of this enzyme was higher in the acidic pH range and that the enzyme had a Km = 4.5 ± 0.5 mM para-nitrophenylphosphate and a Vmax = 2280 ± 158 nM × h-1 × mg protein-1 . In addition, classical acid phosphatase inhibitors, including sodium orthovanadate, decreased enzymatic activity. Sodium orthovanadate was able to inhibit ectophosphatase activity while also inhibiting cell proliferation, adhesion, and migration, which are important processes in tumor progression, especially in metastatic breast cancer MDA-MB-231 cells that have higher ectophosphatase activity than MCF-7 and MCF-10 breast cells.

Visual detection of acid phosphatase based on hollow mesoporous manganese dioxide nanospheres

Acid phosphatase is widely used as a clinical indicator because of its close correlation with a variety of diseases. Herein, a label-free and colorimetric sensing method for detecting the activity of acid phosphatase was constructed based on hollow mesoporous manganese dioxide nanospheres. The nanospheres exhibit superior oxidase-like property and can oxidize colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to yellow TMB2+. Ascorbic acid from acid phosphatase-catalyzed hydrolysis of L-ascorbic acid-2-phosphate will inhibit the oxidization reaction, igniting vivid color variation. On the basis of this obvious multicolor change, the visual detection of acid phosphatase was achieved. Compared with the single-color change, the multicolor colorimetric method is more conducive for naked-eye discrimination. The absorbance difference at 450 nm exhibits a linear relationship with the concentration of acid phosphatase ranging from 1.0 to 25 U L−1, with a detection limit as low as 0.45 U L−1. Acid phosphatase in human serum samples was successfully determined. Moreover, the inhibition efficiency of NaF for acid phosphatase activity was investigated, proving the proposed colorimetric method will be a potential platform for screening acid phosphatase inhibitors and discovering new drugs.

Label-Free Colorimetric Detection of Acid Phosphatase and Screening of Its Inhibitors Based on Biomimetic Oxidase Activity of MnO2 Nanosheets.

In this research, we attempted to develop a sensitive colorimetric sensing strategy for the detection of acid phosphatase (ACP) based on MnO2 nanosheets and explored its applications in screening and evaluating inhibitors of ACP. The MnO2 nanosheets exhibit intrinsic biomimetic oxidase activity, which can catalyze the oxidation of the colorless 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonate) diammonium salt (ABTS) into green oxidized ABTS (oxABTS). Upon the introduction of ACP, l-ascorbic acid-2-phosphate can be dephosphorylated to ascorbic acid, which arouses the disintegration of MnO2 nanosheets into Mn2+ ions. This disintegration weakens the enzyme mimicking activity of the MnO2 nanosheets, leading to the impediment of the oxidation of ABTS. Conversely, in the absence of ACP, the ABTS is rapidly oxidized by MnO2, leading to a significant colorimetric signal change. The absorbance difference at 420 nm displayed a linear relationship with the concentration of ACP ranging from 0.075 to 0.45 mU·mL-1, generating a detection limit of 0.046 mU·mL-1. In the inhibition assays, this sensing platform provided simple detection for parathion-methyl (PM), a representative inhibitor of ACP. The facile evaluation of the inhibitory effect of PM, including its IC50 toward ACP, was also realized.

Colorimetric acid phosphatase sensor based on MoO3 nanozyme.

Nanozymes, or nanomaterials that mimic the behaviors of enzymes, are highly promising materials for biomedical applications because of their excellent chemical stability under harsh conditions, simple preparation method and lower costs compared with natural enzymes. We herein report the intrinsic oxidase-mimicking activity of molybdenum oxide nanoparticles (MoO3 NPs). MoO3 NPs catalyzed the oxidation of colorless 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to green product. The catalytic mechanism of the oxidase-mimicking activity of the MoO3 NPs was investigated in detail using electron spin resonance and a radical inhibition method. The oxidation of ABTS stems from 1O2 generated from the interaction between MoO3 NPs and dissolved oxygen in the solution. Acid phosphatase (ACP) catalyzes the hydrolysis of the ascorbic acid 2-phosphate (AAP) substrate to produce ascorbic acid (AA). AA was found to fade the coloration process of the MoO3 NP-mediated ABTS oxidation. By combining the oxidase-mimicking property of the MoO3 NPs and the ACP-catalyzed hydrolysis of AAP, a novel and simple colorimetric method for detecting ACP was established. The linear range for ACP determination is 0.09-7.3 U/L with a detection limit of 0.011 U/L. This new colorimetric method was successfully applied to the detection of ACP in diluted human serum samples and screening of ACP inhibitors. The present study proposes MoO3 NPs as a new oxidase mimic for establishing various biosensing method.

Peroxo complexes of niobium(V) as potent inhibitors of acid phosphatase and calcineurin enzyme activities

Peroxo complexes of niobium(V) as potent inhibitors of acid phosphatase and calcineurin enzyme activities

Tartrate-resistant phosphatase type 5 in Trypanosoma cruzi is important for resistance to oxidative stress promoted by hydrogen peroxide

Trypanosoma cruzi (the causative agent of Chagas disease) presents a complex life cycle that involves adaptations in vertebrate and invertebrate hosts. As a protozoan parasite of hematophagous insects and mammalian hosts, T. cruzi is exposed to reactive oxygen species (ROS). To investigate the functionality of T. cruzi tartrate-resistant acid phosphatase type 5 (TcACP5), we cloned, superexpressed and purified the enzyme. Purified TcACP5 exhibited a Vmax and apparent Km for pNPP hydrolysis of 7.7 ± 0.2 nmol pNP × μg−1 × h−1 and 169.3 ± 22.6 μM, respectively. The pH dependence was characterized by sharp maximal activity at pH 5.0, and inhibition assays demonstrated its sensitivity to acid phosphatase inhibitors. Similar activities were obtained with saturating concentrations of P-Ser and P-Thr as substrates. The enzyme metabolizes hydrogen peroxide (H2O2) in vitro, and parasites superexpressing this enzyme were more resistant to oxidative stress promoted by H2O2. Taken together, these results suggest that TcACP5 plays a central role in phosphoryl transfer and redox reactions.