Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An electrophoretically mediated microanalysis method for detection of yoctomole (ymol) alkaline phosphatase (ALP) was developed by a combination of on-capillary enzyme-catalyzed reaction and electrochemical detection. In this method, ALP molecules were electrokinetically injected into a capillary of 10 microm i.d. and then electromigrated to the section of the capillary immersed in a warm water bath of 37 degrees C, where ALP reacted for a certain time with disodium phenyl phosphate as the enzyme substrate. ALP could be measured through determining the electroactive product phenol of the enzyme-catalyzed reaction by using electrochemical detection. The phenol concentration was proportional to the mass of ALP. As a catalyst, ALP was not consumed during the reaction, which provided amplification of signal with prolonged the reaction time. In order to enhance the signal-to-noise ratio, the detection end of the capillary was etched to a horn-shape and a single carbon fiber microcylinder electrode of 6 microm in diameter as the working electrode was inserted into the detection end of the capillary. Under these conditions, the mass of ALP as low as 1.2 x 10(-22) mol (72 molecules) or 4.0 x 10(-23) mol (24 molecules) could be detected for the on-capillary reaction time of 15 min or 2h.
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PMID:Monitoring yoctomole alkaline phosphatase by capillary electrophoresis with on-capillary catalysis-electrochemical detection. 1772 15

An amperometric immunosensor for the quantification of Staphylococcus aureus based on the coimmobilization of rabbit immunoglobulin G (RbIgG) and tyrosinase on a mercaptopropionic acid self-assembled monolayer modified gold electrode is reported. A competitive mode in which protein-A-bearing S. aureus cells and antiRbIgG labeled with alkaline phosphatase (AP) compete for the binding sites of immobilized RbIgG was used. Monitoring of the affinity reaction was carried out by the amperometric detection at -0.15 V of phenol generated in the enzyme reaction with AP, at the tyrosinase-modified electrode through the electrochemical reduction of the o-quinone formed. Optimization of the working variables, such as the immunosensor composition and incubation times, the applied potential, the working pH and the concentration of phenyl phosphate used as the AP substrate, was carried out. Under the optimized conditions, both the repeatability of the measurements and the reproducibility of the responses obtained with different immunosensors yielded relative standard deviation values for the steady-state current lower than 10%. The immunosensor showed a dynamic range from 4.4x10(5) to 1.8x10(7) S. aureus cells mL(-1), with a detection limit of 1.7x10(5) cells mL(-1). The limit of detection was remarkably improved by subjecting S. aureus cells to wall lysis by heat treatment. The value obtained was 2.3x10(3) cells mL(-1), which is adequate for the monitoring of S. aureus contamination levels in some foodstuffs. As an application, milk samples spiked with bacteria at the 4.8x10(3) cells mL(-1) level were analyzed.
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PMID:Immunosensor for the determination of Staphylococcus aureus using a tyrosinase-mercaptopropionic acid modified electrode as an amperometric transducer. 1818 27

A single-step end point method is presented for determination of the activity of the enzyme alkaline phosphatase (ALP) using the effect of enhancement of fluorescence of the easily accessible europium(III)-tetracycline 3:1 complex (Eu(3)TC). Its luminescence, peaking at 616 nm if excited at 405 nm, is enhanced by a factor of 2.5 in the presence of phosphate. Phenyl phosphate was used as a substrate that is enzymatically hydrolyzed to form phenol and phosphate. The latter coordinates to Eu(3)TC and enhances its luminescence intensity as a result of the displacement of water from the inner coordination sphere of the central metal. The assay is performed in a time-resolved (gated) mode, which is shown to yield larger signal changes than steady-state measurement of fluorescence. The limit of detection for ALP is 4 micromol L(-1). Based on this scheme, a model assay for theophylline as inhibitor for ALP was developed with a linear range from 14 to 68 micromol L(- 1) of theophylline.
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PMID:Time-resolved fluorescence-based assay for the determination of alkaline phosphatase activity and application to the screening of its inhibitors. 1822 22

In this paper, we have critically evaluated the electrochemical behavior of the products of seven substrates of the enzyme label, alkaline phosphate, commonly used in electrochemical immunosensors. These products (and the corresponding substrates) include indigo carmine (3-indoyl phosphate), hydroquinone (hydroquinone diphosphate), 4-nitrophenol (4-nitrophenol phosphate), 4-aminophenol (p-aminophenyl phosphate), 1-naphthol (1-naphthyl phosphate), phenol (phenyl phosphate), and L-ascorbic acid (2-phospho-L-ascorbic acid). Cyclic voltammetry and amperometry of these products were carried out at glassy carbon (GC), screen-printed carbon (SPC) and gold (Au) electrodes, respectively. Among the products, L-ascorbic acid showed the most sensitive (24.8 microA cm(-2), 12.0 microA cm(-2), and 48.0 microA cm(-2) of 100 microM ascorbic acid at GC, SPC, and Au electrodes, respectively) and well-defined amperometric response at all electrodes used, making 2-phospho-l-ascorbic acid the best substrate in electrochemical detection involving an alkaline phosphatase (ALP) enzyme label. The 2-phospho-L-ascorbic acid is also commercially available and inexpensive. Therefore, it was the best choice for electrochemical detection using ALP as label. Using mouse IgG as a model, an ALP enzyme-amplified sandwich-type amperometric immunosensor was constructed. The immunosensor was designed by electropolymerization of o-aminobenzoic acid (o-ABA) conductive polymer on the surface of GC, SPC, and Au electrodes. The anti-mouse IgG was subsequently attached on the electrode surface through covalent bonding between IgG antibody and the carboxyl groups from poly(o-ABA). Using 2-phospho-L-ascorbic acid as a substrate, the poly(o-ABA)/Au immunosensor produced the best signal (about 297 times of current density response ratio between 1000 ng mL(-1) and 0 ng mL(-1) of mouse IgG), demonstrating that amperometric immunosensors based on a conducting polymer electrode system were sensitive to concentrations of the mouse IgG down to 1 ng mL(-1), with a linear range of 3-200 ng mL(-1) (S.D.<2; n=3), and very low non-specific adsorption.
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PMID:Investigation of the enzyme hydrolysis products of the substrates of alkaline phosphatase in electrochemical immunosensing. 1858 1

Raw milk is a well-established vehicle for the carriage of human pathogens, and many regulatory bodies have consequently mandated compulsory pasteurization as a food safety intervention. The residual activity of alkaline phosphatase (ALP) has historically been used to verify the adequacy of pasteurization of cow's milk. However, there is uncertainty on how the current ALP standards and methods of analysis can be applied to sheep's and goat's milk, which naturally contain different levels of the enzyme than that found in cow's milk. The official ALP methods applied in Canada (colorimetric assay; MFO-3) and in the United States (Fluorophos) were assessed for their ability to detect enzyme activity in raw and pasteurized milk derived from cows, sheep, and goats. The detection limit and the limit of quantitation were 0.8 and 2.02 microg/ml phenol, respectively, for the MFO-3 method and 43 and 85 mU/liter, respectively, for the Fluorophos method. The average ALP levels in raw goat's, cow's, and sheep's milk were 165, 1,562, and 3,512 microg/ml phenol, respectively. Raw milk detection limits, which correspond to raw milk phosphatase levels, were 0.051, 0.485, and 0.023% in cow's, goat's, and sheep's milk, respectively, for the MFO-3 method and 0.007, 0.070, and 0.004%, respectively, for the Fluorophos method. Although both methods can be used for ALP determination in cow's, goat's, and sheep's milk, the Fluorophos assay was superior to the colorimetric MFO-3 method based on sensitivity and time required to complete the analysis.
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PMID:Assessment of the colorimetric and fluorometric assays for alkaline phosphatase activity in cow's, goat's, and sheep's milk. 1881 Aug 73

A bienzyme biosensor based on tyrosinase and horse-radish peroxidase is described in a flow injection analysis and cyclic voltammetry for measurement of phenol. Tyrosinase and horse-radish peroxidase were immobilized on the surface of a glassy carbon electrode by bovine serum albumin and glutaric dialdehyde. Phenol was oxidized by tyrosinase and horse-radish peroxidase via catechol to o-quinone in the presence of oxygen and hydrogen peroxide. The o-quinone was reduced to produce catechol (the substrate recycling) on the electrode surface. The enhanced sensitivity of the bienzyme electrode to phenol was observed in the flow injection system comparing with tyrosinase and horse-radish peroxidase monoenzyme electrodes. The mechanisms for enhanced amperometric response to phenol of bienzyme electrode were discussed. The biosensor was used to detect alkaline phosphatase (ALP). A detection limit of 1.4x10(-15) M ALP (140 zmol/100 mul) was obtained after 1 h incubation with phenyl phosphate.
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PMID:Detection of zeptomolar concentrations of alkaline phosphatase based on a tyrosinase and horse-radish peroxidase bienzyme biosensor. 1896 31

In this study the antioxidant and hepatoprotective properties of free and bound polyphenols from Telfairia occidentalis (darkish green leafy vegetable popularly used in soup and folk medicine for the management of many diseases in Nigeria) leaves were compared. Free soluble polyphenols were extracted with 80% acetone, while the bound polyphenols were extracted from the acid and alkaline hydrolyzed residue of the leaf from free soluble polyphenols using ethyl acetate. The total phenol, DPPH free radical scavenging ability and reducing property were determined; subsequently the ability of the extracts to prevent acetaminophen (megadose) induced liver damage in rats were also assessed. Change in serum Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), alkaline phosphatase (ALP), albumin, total protein and bilirubin were also determined. The results of the study revealed that the free soluble polyphenols content in the vegetable were significantly higher (p<0.05) than the bound polyphenols. Also, the free soluble polyphenols had a significantly higher antioxidant activity as typified by their higher reducing Power (0.28 OD700) and free radical scavenging ability (83.3%) than the bound polyphenols [reducing power (0.22 OD700), free radical scavenging ability (66.6%)]. Daily intubation of wistar strain albino rat's with 100 mg/mL/day for 7 days caused a significant increase (p<0.05) in serum alkaline phosphatase (ALP), Glutamate Oxaloacetate Transaminase (GOT) and Glutamate Pyruvate Transaminase (GPT), while there was no significant change (p>0.05) in serum bilirubin, albumin, globulin and total proteins in the rats. However, simultaneous intubations of some of the rat with 10 mg or 20 mg mL(-1) of T. occidentalis leaf extract (free soluble or bound polyphenols) along side with the acetaminophen caused a significant decrease (p<0.05) in serum ALP, GOT and GPT (except those intubated with bound polyphenols). Free soluble polyphenols had higher protective effect on the liver than the bound polyphenols; however there action were not dose-dependent. It could be inferred that both soluble free and bound polyphenols extracts of T. occidentails leaf have antioxidant and hepatoprotective properties, however soluble free polyphenols had significantly higher antioxidant and hepatoprotective properties than the bound polyphenols.
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PMID:Antioxidant and hepatoprotective properties of polyphenol extracts from Telfairia occidentalis (fluted pumpkin) leaves on acetaminophen induced liver damage. 1907 82

An ultrasensitive electrochemical method for determination of DNA is developed based on counting of single magnetic nanobeads (MNBs) corresponding to single DNA sequences combined with a double amplification (DNA amplification and enzyme amplification). In this method, target DNA (t-DNA) is captured on a streptavidin-coated substrate via biotinylated capture DNA. Then, MNBs functionalized with first-probe DNAs (p1-DNA-MNBs) are conjugated to t-DNA sequences with a ratio of 1:1. Subsequently, the p1-DNA-MNBs are released from the substrate via dehybridization. The released p1-DNA-MNBs are labeled with alkaline phosphatase (AP) using biotinylated second-probe DNAs (p2-DNAs) and streptavidin-AP conjugates. The resultant AP-p2-DNA-p1-DNA-MNBs with enzyme substrate disodium phenyl phosphate (DPP) are continuously introduced through a capillary as the microsampler and microreactor at 40 degrees C. AP on the AP-p2-DNA-p1-DNA-MNBs converts a huge number of DPP into its product phenol, and phenol zones are produced around each moving AP-p2-DNA-p1-DNA-MNB. The phenol zones are continuously delivered to the capillary outlet and detected by a carbon fiber disk bundle electrode at 1.05 V. An elution curve with peaks is obtained. Each peak is corresponding to a phenol zone relative to single t-DNA sequence. The peaks on the elution curve are counted for quantification. The number of the peaks is proportional to the concentration of t-DNA in a range of 5.0 x 10(-16) to 1.0 x 10(-13) mol/L.
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PMID:Ultrasensitive electrochemical DNA assay based on counting of single magnetic nanobeads by a combination of DNA amplification and enzyme amplification. 1919 8

This study sought to characterize the distribution of phenols and antioxidant activities in hot short pepper (Capsicum frutescens var. abbreviatum) and their inhibition of cyclophosphamide-induced oxidative stress in rat's brain. The total phenol content and antioxidant activities of pepper flesh (pericarp) and seeds were determined in vitro and in vivo. The results of the study revealed that intraperitoneal administration of cyclophosphamide (75mg/kg of body weight) caused a significant increase (P<0.05) in the malondialdehyde (MDA) content of the brain; however, there was a significant decrease (P<0.05) in the brain MDA content, in those of rats fed diet containing pepper; the flesh showed a higher inhibitory effect. In addition, dietary inclusion of the pepper (seed and flesh) also caused a dose-dependent inhibition of serum glutamate oxaloacetate transaminase (SGOT), glutamate pyruvate transaminase (SGPT), alkaline phosphatase and total bilirubin; likewise, dietary inclusion of the flesh inhibited MDA production than the seeds. The higher inhibition of oxidative stress in brain and serum enzymes and metabolites by the flesh could be attributed to its significantly higher (P<0.05) total phenol content, reducing power and free-radical scavenging ability. Therefore, dietary hot short pepper (Capsicum frutescens L. var. abbreviatum) could prevent cyclophosphamide-induced oxidative stress in brain; although the flesh is a better protectant, the possible contributory role of the seeds cannot be neglected. However, this protective effect of the pepper could be attributed to their antioxidant properties.
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PMID:Cyclophosphamide-induced oxidative stress in brain: protective effect of hot short pepper (Capsicum frutescens L. var. abbreviatum). 1944 89

Carvacrol (2-methyl-5-(1-methylethyl)-phenol) is a predominant monoterpenic phenol occuring in many essential oils of the family Labiatae including, Origanum, Satureja, Thymbra, Thymus, and Corydothymus species. The present study was designed to investigate the effect of carvacrol on D-galactosamine (D-GalN)-induced hepatotoxicity in rats. D-GalN-hepatotoxic rats exhibited elevation in the serum bilirubin level and the activities of the hepatic marker enzymes aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and gamma glutamyl transpeptidase. In the plasma, increased levels of very low density lipoprotein cholesterol and low density lipoprotein cholesterol and decreased high density lipoprotein cholesterol were observed. Further, an increase in the levels of total cholesterol, phospholipids, triglycerides, and free fatty acids in the plasma and tissues of liver and kidney were observed in hepatotoxic rats. The administration of carvacrol for 21 days prevented and improved these parameters toward normalcy. The results suggest that carvacrol affords a significant hepatoprotective and hypolipidemic effect against D-GalN-induced-rats.
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PMID:Antihyperlipidemic effect of carvacrol on D-galactosamine-induced hepatotoxic rats. 1960 92


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