scholarly journals Kinetic analysis of chemical reactions coupled to an enzymic step. Application to acid phosphatase assay with Fast Red

1984 ◽  
Vol 223 (3) ◽  
pp. 633-638 ◽  
Author(s):  
J Escribano ◽  
F García-Carmona ◽  
F García-Cánovas ◽  
J L Iborra ◽  
J A Lozano
Keyword(s):  
Acid Phosphatase ◽  
Chemical Reactions ◽  
Rate Constants ◽  
Diazonium Salt ◽  
Specific Rate ◽  
Fast Red ◽  
Temperature Ranges ◽  
Lag Period ◽  
Ph Range ◽  
Phosphatase Assay

Acid phosphatase assay with alpha-naphthyl phosphate as substrate and the use of diazonium salt (Fast Red TR) for chromophore formation was kinetically analysed as a system of two chemical reactions coupled to an enzymic reaction. This system follows a mechanism defined as enzymic-chemical-chemical (EzCC). The accumulation of chromophore with reaction time presented a marked lag period, which was only dependent on the rate constants of the chemical reactions and was independent of the enzymic step. The specific rate constants of each chemical step were determined in 3.8-5.0 pH and 10-35 degrees C temperature ranges. Thermodynamic parameters of the chemical steps were also obtained. Measurement of acid phosphatase activity can be carried out in the pH range 3.8-5.0 (4.8 was optimal pH) without the need to eliminate the lag period.

scholarly journals Continuous assay for acid phosphatase using 1-naphthyl phosphate as a substrate.

1997 ◽  
Vol 44 (4) ◽  
pp. 853-860 ◽  
Author(s):  
E Luchter-Wasylewska
Keyword(s):  
Aqueous Solution ◽  
Steady State ◽  
Acid Phosphatase ◽  
Reverse Micelles ◽  
Prostatic Acid Phosphatase ◽  
Precise Determination ◽  
Ph Range ◽  
Phosphatase Assay ◽  
Kinetics Of

The described continuous acid phosphatase assay is based on kinetics of the release of 1-naphthol in the course of the enzyme-catalyzed hydrolysis of 1-naphthyl phosphate, measured at 320 nm in aqueous solution and at 322 nm in sodium-bis(2-ethylhexyl)sulfosuccinate isooctane-water reverse micelles in a broad pH range (1.0-8.2). The method allows precise determination of the initial rate of the reaction and therefore may be used in the steady-state and pre-steady-state studies on the phosphatase-catalyzed reaction. The kinetic parameters (Km and kcat) for human prostatic acid phosphatase in aqueous solution and in reverse micelles, at pH 3.8, 4.5 and 5.7, by the proposed 1-naphthyl phosphate assay have been determined.

Trypanosoma brucei: Ecto-Phosphatase Activity Present on the Surface of Intact Procyclic Forms

1997 ◽  
Vol 52 (5-6) ◽  
pp. 351-358 ◽  
Author(s):  
Eloise C. Fernandes ◽  
José R. Meyer-Fernandes ◽  
Mário A. C. Silva-Neto ◽  
Anibal E. Vercesi
Keyword(s):  
Acid Phosphatase ◽  
Cell Surface ◽  
Cell Viability ◽  
Phosphatase Activity ◽  
Trypanosoma Brucei ◽  
Intact Cells ◽  
Vanadate Inhibition ◽  
Rate Of Hydrolysis ◽  
Ph Range

Abstract The results presented in this paper indicate that procyclic forms of Trypanosoma brucei possess a phosphatase activity detected in the external cell surface able to hydrolyze about 0.7 nmol ∙ mg−1. min−1 p-nitrophenylphosphate. A faster rate of hydrolysis was observed when membrane-enriched fractions were used. This activity is weakly sensitive to 1 mᴍ NaF, 10 mᴍ tartrate and 10 mᴍ levamizole but strongly inhibited by 0.1 mᴍ vanadate. Inhibition by both NaF and vanadate have a competitive character. This phosphatase activity decreases by increasing the pH from 6.8 to 8.4, a pH range in which cell viability was maintained during at least 1 hour. In the membrane-enriched fractions this phosphatase activity showed to be an acid phosphatase. In addition, intact cells could catalyze the dephosphorylation of [32P]phosphocasein phosphorylated at serine and threonine residues.

The Role of Starting Potential in the Kinetics of Chemical Reactions under Electrodeless Discharge

1970 ◽  
Vol 25 (11) ◽  
pp. 1772
Author(s):  
T.S.R Ao ◽  
A. Patil
Keyword(s):  
Gas Phase ◽  
Chemical Reactions ◽  
Electric Discharge ◽  
Specific Rate ◽  
Gas Phase Reactions ◽  
Electrodeless Discharge ◽  
First Order ◽  
Kinetics Of

Abstract It has been shown that in kinetically first order gas phase reactions occuring under electric discharge, such as the decomposition of N2O, the application, at various initial pressures, of the same multiple of the respective starting potential ensures that the reaction occurs at the same specific rate.

Kinetic Method for Determining Acid Phosphatase Activity in Serum with Use of the "CentrifiChem"

1972 ◽  
Vol 18 (8) ◽  
pp. 841-844 ◽  
Author(s):  
Diane L Fabiny-Byrd ◽  
Gerhard Ertingshausen
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Kinetic Method ◽  
Reaction Rates ◽  
Phosphatase Activities ◽  
Fast Red ◽  
Presence And Absence

Abstract Acid phosphatase activity is determined by splitting 1-naphthyl phosphate, concurrently diazotizing the released 1-naphthol with Fast Red TR, and measuring the resulting color. The test is performed in the presence and absence of tartrate. Reaction rates can be continuously monitored, and their difference is proportional to acid phosphatase activity that is inhibited by tartrate. Results for sera with normal and increased acid phosphatase activities are presented and three different methods for acid phosphatase are compared. The kinetic blank used in the reaction eliminates all nonenzymatic contributions to substrate splitting.

ChemInform Abstract: REACTION OF INDOLES WITH A DIAZONIUM SALT (FAST RED B)

1973 ◽  
Vol 4 (30) ◽  
pp. no-no
Author(s):  
THOMAS F. SPANDE ◽  
GEORGE G. GLENNER
Keyword(s):  
Diazonium Salt ◽  
Fast Red
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