Interaction between pyridine nucleotide coenzymes and heme proteins as a possible source of error in assay of activities of coenzyme-linked enzyme.

1989 ◽  
Vol 35 (10) ◽  
pp. 2129-2133 ◽  
Author(s):  
M D Jeyasingham ◽  
O E Pratt ◽  
H K Roopral
Keyword(s):  
Pyridine Nucleotide ◽  
Peak Height ◽  
Heme Group ◽  
Ultraviolet Absorbance ◽  
The Third ◽  
Spectral Shifts ◽  
Muscle Breakdown ◽  
Activity Of Enzymes ◽  
Source Of Error ◽  
Absorbance Spectra

Abstract The ultraviolet absorbance spectra of pyridine nucleotide coenzymes change in the presence of heme-containing proteins. The positions of each of the two main absorbance peaks of NADH are shifted progressively towards shorter wavelengths in the presence of increasing concentrations of hemoglobin, and the third peak, at 220 nm, disappears altogether. Similar changes are seen in the spectra of NAD+ and NADPH, and similar effects on these spectra are produced by myoglobin and cytochrome c, but not by comparable concentrations of albumin. The spectral shifts are generally accompanied by a decreased peak height. This finding may help explain problems reported by previous workers in the measurement of the activity of enzymes such as transketolase or lactate dehydrogenase in erythrocyte hemolysates. Errors may be considerable if allowance is not made for this effect, especially if the concentration of heme protein in the spectrophotometer cuvette much exceeds 1 g/L. The interaction appears to indicate some form of bonding, occurring generally between pyridine nucleotide coenzymes and the heme group in proteins. We relate the findings to measurement of activities of pyridine nucleotide-linked enzymes in erythrocyte lysates and in plasma containing myoglobin after muscle breakdown.

Identification of Plant Material by Its Phenolic Content

1967 ◽  
Vol 50 (3) ◽  
pp. 727-734
Author(s):  
M Bonner Duggan
Keyword(s):  
Thin Layer ◽  
Plant Material ◽  
Phenolic Content ◽  
Pyrus Communis ◽  
Flavonol Glycosides ◽  
Ultraviolet Absorbance ◽  
Flavonoid Compounds ◽  
Phenolic Constituents ◽  
Minor Compounds ◽  
Absorbance Spectra

Abstract Methods have been developed to extract and chroniatograph phenolic constituents of Mains sylvestris and Pyrus communis fruits. Differences in the occurrence of flavonoid compounds between the two fruits and between pulp and peel in a given fruit were compared; the flavonol glycosides most conveniently demonstrated the differences. Five major and three minor flavonol glycosides from Stayman apples and two major and two minor ones from Packingham pears were separated by thin layer chromatograpliy. All of the major and some of the minor compounds were also described by ultraviolet absorbance spectra. Studies show that fruits can be distinguished on the basis of chromatographic patterns of the flavonol glycosides and that the results can be confirmed by their ultraviolet absorbance spectra

UV-microscopic analysis of acetylated spruce and birch cell walls

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 483-488 ◽  
Author(s):  
Christian Hansmann ◽  
Manfred Schwanninger ◽  
Barbara Stefke ◽  
Barbara Hinterstoisser ◽  
Wolfgang Gindl
Keyword(s):  
Cell Walls ◽  
Middle Lamella ◽  
Microscopic Analysis ◽  
Weight Percent ◽  
Cellular Level ◽  
Uv Spectrum ◽  
Spectral Shifts ◽  
Microscopy Analysis ◽  
Absorbance Peak ◽  
Absorbance Spectra

Abstract Spruce and birch earlywood was acetylated to different weight percent gains using three different acetylation procedures. The absorbance spectra of secondary cell wall and compound cell corner middle lamella were determined by means of UV microscopy. Analysis of the spectra showed that the characteristic lignin absorbance peak in the UV spectrum of wood around 280 nm shifted to shorter wavelengths in acetylated samples. A distinct relationship between achieved weight percent gains after acetylation and observed spectral shifts could be established revealing a certain potential to measure acetylation on a cellular level by means of UV microscopy.

scholarly journals Effect of pesticide Glyphosate Aqua in liver enzymes activity of Barbus sharpeyi

2016 ◽  
Vol 13 (2) ◽  
pp. 240-246
Author(s):  
Baghdad Science Journal
Keyword(s):  
Liver Enzymes ◽  
Fish Nutrition ◽  
Control Group ◽  
Average Weight ◽  
Biochemical Tests ◽  
The Third ◽  
Nutrition Research ◽  
Barbus Sharpeyi ◽  
Activity Of Enzymes ◽  
And Control

The present study was designed in the aquaculture and fish nutrition research aquarium in the College of Veterinary Medicine/Baghdad University from a period 1/3 to 1/6/2013 to investigate the toxicity of the herbicide glyphosate aqua on Barbus sharpeyi fish. Fish fingerlings were used with average weight between 10 – 15 gm to measure the (LC50), and 200 fingerlings were used to know the acute and chronic toxic effect for the herbicide. The fingerlings were randomly distributed as 10 fish for each aquarium. Fish were divided into four treatments and control group (without addition of herbicide). The first processing with a concentration of 0.415 mg/L for a duration of exposure 90 days, the second processing group with a concentration 0.415 mg/L for 15 days, while the third group was treated with 0.207 mg/L of the herbicide for a duration of exposure, the forth group was exposed to 0.207 mg/L for 15 days only. The study aimed to determine the extent of the effect of the pesticide in the activity of liver enzymes, which included Alkaline phosphatase (ALP), Aspartate amino transfers (AST) and Alanine amino transfers (ALT). The results of biochemical tests for liver enzymes to fish experience has shown a rise in activity of enzymes which increased with duration of exposure. The first and the third treatments has a significant differences (P ?0.05) compared with control group. Results of the experiment to improvement in the health status of fish in second and forth treatments compared to control group.

Photooxidation of NADH by 2,3-butanedione: a potential source of error in studies on active site arginyl residues

1979 ◽  
Vol 57 (6) ◽  
pp. 977-979 ◽  
Author(s):  
Mona Homyk ◽  
P. D. Bragg
Keyword(s):  
Aqueous Solution ◽  
Active Site ◽  
Pyridine Nucleotide ◽  
Pyridine Nucleotides ◽  
Active Site Residues ◽  
Potential Source ◽  
Source Of Error ◽  
Arginyl Residues

Incubation of NADH or NADPH with 2,3-butanedione in aqueous solution results in photooxidation of the reduced pyridine nucleotides under conditions of ordinary laboratory lighting. Maximum rates of photooxidation are obtained at pH 7 and with light at a wavelength of 410 nm. This reaction could lead to artifactual results in experiments on the role of arginyl groups in enzymes in which a reduced pyridine nucleotide is used to protect the active site residues from modification by 2,3-butanedione.

The technique of measuring thrombin generation with fluorogenic substrates: 1. Necessity of adequate calibration

2008 ◽  
Vol 100 (08) ◽  
pp. 343-349 ◽  
Author(s):  
Erik De Smedt ◽  
Raed Al Dieri ◽  
Henri M. H. Spronk ◽  
Karli Hamulyak ◽  
Hugo ten Cate ◽  
...  
Keyword(s):  
Fluorescence Quenching ◽  
Thrombin Generation ◽  
Systematic Errors ◽  
Peak Height ◽  
Fluorogenic Substrates ◽  
Parallel Sample ◽  
Coefficients Of Variation ◽  
Individual Calibration ◽  
Source Of Error ◽  
Preanalytical Conditions

SummaryIn fluorogenic thrombin generation (TG) measurement the concentrations of thrombin are obtained from the course of fluorescence intensity. Because of fluorescence quenching, in one series of normal plasmas (n=60), the rate of fluorescence increase at fixed thrombin activity was 70 ± 13% of that in buffer, in another (n= 139) 75 ± 8%. Using a calibration factor (CF) measured in buffer therefore underestimates thrombin concentrations in plasma and introduces a source of error. A fixed CF also neglects the 25 – 35% increase of CF during the experiment and thus distorts the form of the TG curve so that the ETP cannot be determined. Continuous individual calibration (CIC), in which CF is determined continuously in a parallel sample, avoids such systematic errors but adds random error because the thrombin course is calculated from two different measurements. We determined the intra-individual coefficients of variation (CV) of the peak-height and ETP as obtained with CIC to those obtained with a fixed CF measured in buffer. With the fixed CF, the CVs varied between 18% and 49%; with CIC they lowered to 4–7% (n=5x12), i.e. in a range allowing clinical application. It is shown that CIC can be discarded for the measurement of peak thrombin values and replaced by comparison to a reference plasma only if quenching is not a systematic confounder. This was shown to be the case in the set of 139 normal plasmas but not in the set used for determining the intraindividual CVs, a difference that may depend upon preanalytical conditions.

Ultraviolet Spectroscopic Study of Ferric Iron Solutions

1980 ◽  
Vol 34 (3) ◽  
pp. 377-380 ◽  
Author(s):  
Mary F. Brown ◽  
Dana R. Kester
Keyword(s):  
Ionic Strength ◽  
Ferric Iron ◽  
Gaussian Function ◽  
Low Ph ◽  
Absorption Bands ◽  
Experimental Conditions ◽  
Band Maximum ◽  
Ultraviolet Absorbance ◽  
Constant Ph ◽  
Absorbance Spectra

Ultraviolet absorbance spectra of ferric iron solutions of varying iron concentrations maintained at a constant pH of 1.0 and a constant ionic strength of 0.1 were studied. The experimental conditions of low pH minimized the formation of the hydrolytic FeOH2+ and Fe(OH)2+ species; thus, the spectra of iron solutions containing principally the Fe3+ species were recorded. The digitized spectral data were used to establish a model for the Fe3+ absorption spectrum that involves a Gaussian function with three parameters for each of the two absorption bands. These parameters were the wavenumber of the band maximum, ν̄max, the full width at half maximum intensity, Δν̄1/2, and the absorptivity of the band maximum, εmax. This study provided estimates for these parameters at 25°C for 0.1 ionic strength media.

Cecal enzyme activity in gilts following experimentally induced Fusarium mycotoxicosis

2015 ◽  
Vol 18 (1) ◽  
pp. 191-197 ◽  
Author(s):  
K. Śliżewska ◽  
A. Nowak ◽  
M. Piotrowska ◽  
Z. Żakowska ◽  
M. Gajęcka ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
The Third ◽  
Activity Of Enzymes ◽  
Descending Colon ◽  
Experimentally Induced

AbstractThe objective of the presented study was to examine the influence ofFusariummycotoxins (zearalenone – ZEN and deoxynivalenol – DON), administered separately and in combination, on the activity of cecal enzymes (β-glucosidase and β-glucuronidase) in gilts which were fed fodder contaminated with these mycotoxins. The activity of β-glucosidase and β-glucuronidase varied in the range of 0.170-1.236 μmol · h−1· mg−1and 8.701-96.704 μmol · h−1· mg−1, respectively. In the first two weeks, the toxins had no significant effect on the activity of β-glucosidase and β-glucuronidase in the ascending and descending colon. After week 3 and later on, ZEN and DON administered as a mixture led to the highest increase in the activity of both enzymes. Administered separately, DON affected the activity of enzymes more than ZEN. From the third week of the experiment, an increase in the activity of CW β-glucosidase and β-glucuronidase was observed.

Liquid-chromatographic measurement of amino acids in biological samples after formation of phenylthiohydantoin derivatives.

1984 ◽  
Vol 30 (6) ◽  
pp. 851-855 ◽  
Author(s):  
H G Biggs ◽  
L J Gentilcore
Keyword(s):  
Amino Acids ◽  
Biological Samples ◽  
Internal Standard ◽  
Peak Height ◽  
Reversed Phase ◽  
Ultraviolet Absorbance ◽  
Organic Solvent Extraction ◽  
Chromatographic Measurement ◽  
Assay Precision ◽  
Liquid Chromatographic

Abstract In this method for measuring amino acids in urine, serum, and tissue, the amino acids to be assayed and the internal standard, L-norleucine, are converted to phenylthiohydantoins , isolated by organic solvent extraction, separated by reversed-phase "high-pressure" liquid chromatography, and detected by ultraviolet absorbance. The analytes are identified by retention times and quantified by comparing peak heights with that of the internal standard. The peak-height ratios vary linearly with concentrations of 50 to 500 mg/L, corresponding to the concentration range usually found in biological samples. Detection limits are 5 to 20 mg/L. Inter- and intra-assay precision (CV) varies between 1 and 26%. Average analytical recoveries range between 67 and 100%.

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