A colorimetric assay for the determination of acetyl xylan esterase or cephalosporin C acetyl esterase activities using 7-amino cephalosporanic acid, cephalosporin C, or acetylated xylan as substrate

2007 ◽  
Vol 369 (2) ◽  
pp. 210-217 ◽  
Author(s):  
Irene Martínez-Martínez ◽  
Silvia Montoro-García ◽  
José Daniel Lozada-Ramírez ◽  
Álvaro Sánchez-Ferrer ◽  
Francisco García-Carmona
Keyword(s):  
Colorimetric Assay ◽  
Cephalosporin C ◽  
Acetyl Xylan Esterase ◽  
Acetyl Esterase ◽  
Esterase Activities

Development of a colorimetric protein phosphorylation assay for detecting cyanobacterial toxins

1995 ◽  
Vol 31 (5-6) ◽  
pp. 47-49 ◽  
Author(s):  
C. Ash ◽  
C. MacKintosh ◽  
R. MacKintosh ◽  
C. R. Fricker
Keyword(s):  
Protein Phosphorylation ◽  
Colorimetric Assay ◽  
Cyanobacterial Toxins ◽  
Sensitive Determination

A new colorimetric assay is described, based on inhibition of protein phosphotases, that enables the rapid, simple and sensitive determination of the concentration of toxins from cyanobacteria.

The Need for Using An Enzymatic Colorimetric Assay in Creatinine Determination of Peritoneal Dialysis Solutions

1990 ◽  
Vol 10 (1) ◽  
pp. 89-92 ◽  
Author(s):  
Liliane Larpent ◽  
Christian Verger
Keyword(s):  
Peritoneal Dialysis ◽  
Reliable Method ◽  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Peritoneal Membrane ◽  
Creatinine Kinetics ◽  
Dialysis Solutions ◽  
Peritoneal Dialysis Solutions ◽  
Enzymatic Test

The fate of the peritoneal membrane on continuous ambulatory peritoneal dialysis (CAPD) is usually evaluated through the modification of its permeability to various solutes as glucose, creatinine, and urea. Therefore, the accuracy of the methods used for measurements of creatinine is of great importance. A particular problem does exist for creatinine determination as it may be influenced by the presence of glucose. We studied a new enzymatic colorimetric method for creatinine determination in peritoneal dialysis solutions which contain high dextrose concentrations. Creatinine was measured in plasma, urine, and dialysate from 18 patients on CAPD and in pure dextrose solutions, with an enzymatic test (Boehringer Mannheim) and with Jaffe's reaction on two different analyzers: Astra (Beckman) and Eris (Merck). Creatinine results were similar with both assays (Jaffe's reaction and enzymatic test) when measured in blood and urine. However the Jaffe's reaction gave higher creatinine results than the enzymatic test (p < 0.001), when assays were performed in peritoneal dialysis solutions and in pure glucose solutions. In addition, it appeared that other components of dialysis solutions, mainly calcium chloride, influenced unpredictably the results of creatinine with the Jaffe's reaction. We conclude that specific enzymatic test is a more accurate and reliable method to evaluate creatinine kinetics through the peritoneal membrane when determined in CAPD solutions.

A novel colorimetric assay for the determination of lysophosphatidic acid in plasma using an enzymatic cycling method

2003 ◽  
Vol 333 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Tatsuya Kishimoto ◽  
Takeshi Matsuoka ◽  
Shigeyuki Imamura ◽  
Koji Mizuno
Keyword(s):  
Lysophosphatidic Acid ◽  
Colorimetric Assay ◽  
Enzymatic Cycling

Determination of rat serum esterase activities by an HPLC method using S-acetylthiocholine iodide and p-nitrophenyl acetate

2008 ◽  
Vol 381 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Matthias Koitka ◽  
Joachim Höchel ◽  
Detlev Obst ◽  
Antje Rottmann ◽  
Hille Gieschen ◽  
...  
Keyword(s):  
Hplc Method ◽  
Rat Serum ◽  
Acetylthiocholine Iodide ◽  
Esterase Activities

Modification of the Stewart biphasic colorimetric assay for stable and accurate quantitatitive determination of Pluronic and Tetronic block copolymers for application in biological systems

2007 ◽  
Vol 361 (2) ◽  
pp. 287-293 ◽  
Author(s):  
Othman Al-Hanbali ◽  
Nneka M. Onwuzo ◽  
Kenneth J. Rutt ◽  
Christopher M. Dadswell ◽  
S. Moein Moghimi ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Colorimetric Assay ◽  
Biological Systems

Fluorescent and colorimetric assay for determination of Cu(II) and Hg(II) using AuNPs reduced and wrapped by carbon dots

2021 ◽  
Vol 189 (1) ◽  
Author(s):  
Yuxi Li ◽  
Lu Tang ◽  
Chenxue Zhu ◽  
Xunyong Liu ◽  
Xing Wang ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Colorimetric Assay

Quantitative Determination of Thiourea in Citrus Fruits

1977 ◽  
Vol 60 (3) ◽  
pp. 699-701
Author(s):  
Bernadette Mandrou ◽  
Suzanne Brun ◽  
Amara Kingkate
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Extraction Technique ◽  
Citrus Fruits ◽  
Alumina Column ◽  
Orange Peels ◽  
Ultraviolet Reflectance ◽  
Spectrometric Measurements ◽  
Colorimetric Reaction

Abstract A quantitative method for thiourea determination in orange peels is proposed, with direct reflectance spectrometric measurements on chromatoplates. Thiourea is separated on a silica gel plate with methanol-chloroform (10+90), and the spots are characterized with 2,6-dichloroquinone chloroimide; this colorimetric reaction is unstable, so thiourea is quantitated on the chromatogram by direct ultraviolet reflectance spectrometric measurements at 240 nm. Comparison between this method and the AOAC colorimetric method shows interferences and higher results in the colorimetric assay. By slightly modifying the extraction technique, such as purifying the extract on an alumina column, it is possible to decrease these interferences and to avoid erroneous results with the AOAC colorimetric method. For both methods, colorimetry in solution and reflectometry on chromatoplates, applied after the proposed extraction technique, the sensitivity is about 1 ppm and the reliabilities are similar.

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