Automated kinetic determination of lactate dehydrogenase isoenzymes in serum.

1977 ◽  
Vol 23 (10) ◽  
pp. 1928-1930 ◽  
Author(s):  
L H Bernstein
Keyword(s):  
Lactate Dehydrogenase ◽  
Kinetic Method ◽  
Previous Method ◽  
Kinetic Determination ◽  
Steady State Kinetic ◽  
Enzyme Subunits ◽  
Isoenzyme Composition ◽  
State Kinetic ◽  
Lactate Dehydrogenase Isoenzymes

Abstract A steady-state kinetic method has been revised for measuring lactate dehydrogenase isoenzyme activities, which relates the inhibition of heart-type isoenzyme activity to the overall isoenzyme composition of the enzyme subunits. The method depends on the pH-dependent formation of an inhibitory ternary complex by the heart-type isoenzyme with NAD+ and pyruvate (if the reaction is measured by NADH oxidation). A preincubation step in the previous method is eliminated. The isoenzymes are measured by measuring the reduction of pyruvate in two different concentrations, which favor either the total or fractional activity, depending on the concentrations of pyruvate and the percentage of heart-type subunits. The method has been adapted to a centrifugal analyzer, which has speeded automated isoenzyme determinations, with an accuracy comparable to that for electrophoretic methods.

scholarly journals Kinetic determination of As(III) in solution

2003 ◽  
Vol 68 (10) ◽  
pp. 765-769
Author(s):  
Sofija Rancic ◽  
Rangel Igov ◽  
Todor Pecev
Keyword(s):  
Acid Solution ◽  
Relative Error ◽  
Reaction Rate ◽  
Kinetic Method ◽  
Kinetic Equations ◽  
Strong Acid ◽  
Kinetic Determination

A new reaction is suggested and a new kinetic method is elaborated for the As(HI) traces determination in solution, on the basis of their catalyzing effect on komplexon III (EDTA) oxidation by KMnO4 in a strong acid solution (H2SO4). Using a spectrophotometric technique, a sensitivity of 72 ng/cm3 As(IIl) was achieved. The relative error of method varies from 5.5 to 13.9 % for As(HT) concentration range from 83 to 140 ng/cm-1. Appropriate kinetic equations are formulated and the influence of some other ions, including the As(V), upon the reaction rate is tested.

Ten electrophoretic methods compared with a selected method for quantifying lactate dehydrogenase isoenzymes in serum.

1988 ◽  
Vol 34 (9) ◽  
pp. 1885-1890 ◽  
Author(s):  
G C Moses ◽  
M L Ross ◽  
A R Henderson
Keyword(s):  
Lactate Dehydrogenase ◽  
Reference Method ◽  
Average Difference ◽  
Correlation Analyses ◽  
Different Types ◽  
Lactate Dehydrogenase Isoenzymes

Abstract Using the Selected Method of McKenzie and Henderson (Selected Methods Clin Chem 1983;10:59-67) as a reference method, we compared the performance of 10 commercially available methods for determination of lactate dehydrogenase (LD, EC 1.1.1.27) isoenzymes. Results were expressed as percentage of total LD activity, as determined with two different types of densitometers shown to have an average difference less than 1.4% for each isoenzyme. All methods gave generally comparable results, as judged by Bland-Altman plots and correlation analyses. However, in general, estimates by the commercial methods for LD-1, LD-2, and LD-3 were lower, and for LD-4 and LD-5 were higher than with the Selected Method. The overall CV was less than 20% for all methods and isoenzymes, except for LD-4 and LD-5 by the Beckman Paragon, Helena LD-VIS, Gel LDH, Gel PC, and Iso Dot, Gelman LDH Isozyme, and Sebia Hydragel assays, for which it was greater than 20%. Overall, accuracy was best with the Helena Iso Dot and LD-VIS assays, followed by the Corning LD Flur assay; accuracy was poorest with the Gelman LDH Isozyme, Sebia Hydragel, and Beckman Paragon assays.

scholarly journals The determination of lactate dehydrogenase isoenzymes in normal human muscle and other tissues

1967 ◽  
Vol 105 (2) ◽  
pp. 599-604 ◽  
Author(s):  
A. E. H. Emery
Keyword(s):  
Lactate Dehydrogenase ◽  
Gel Electrophoresis ◽  
Human Muscle ◽  
Starch Gel Electrophoresis ◽  
Fibrous Connective Tissue ◽  
Starch Gel ◽  
Normal Human ◽  
Lactate Dehydrogenase Isoenzymes ◽  
Good Agreement

1. A technique has been developed, based on preferential inhibition by urea, for determining the amounts and proportions of the M and H sub-units of lactate dehydrogenase (referred to as LDH-M and LDH-H respectively) in human tissues, including muscle. 2. There was good agreement between the results obtained with urea inhibition and those obtained with starch-gel electrophoresis. 3. With increasing age there was a significant decrease in the total amount of lactate dehydrogenase and the amount of LDH-M in skeletal muscle. This could not be accounted for by the replacement of functioning muscle tissue by fibrous connective tissue. 4. The proportion of LDH-M was less in certain muscles (e.g. soleus and extra-ocular) than in other muscles (e.g. gastrocnemius and rectus abdominis). 5. The proportions of LDH-M and LDH-H did not differ significantly in different superficial limb muscles and were not significantly affected by either age or sex. 6. Specimens of muscle from 86 different individuals (all Europeans) have been subjected to electrophoresis, but no variants of lactate dehydrogenase isoenzymes have been found.

scholarly journals Analytical application of acidic victoria blue 4R mixture with KBrO3 for the kinetic determination of traces of antimony(III) by spectrophotometry

2012 ◽  
Vol 31 (1) ◽  
pp. 29
Author(s):  
Violeta Mitić ◽  
Snežana Nikolić-Mandić ◽  
Vesna Stankov-Jovanović
Keyword(s):  
Reaction Rate ◽  
Kinetic Method ◽  
Operating Conditions ◽  
Rate Equations ◽  
Optimum Operating ◽  
Acid Media ◽  
Kinetic Determination ◽  
Hydrochloric Acid Media ◽  
Optimized Conditions

The present paper describes a simple, selective and sensitive kinetic method for the determination of trace amounts of Sb(III) in the presence of Sb(V) based on its inhibition effect on the redox reaction between bromate and Victoria blue 4R (V.B. 4-R) in hydrochloric acid media. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of V.B. 4-R at 596.3 nm. Optimum operating conditions regarding reagent concentrations were established. The optimized conditions yielded a theoretical detection limit of 1.30·10‒8 g cm–3 Sb(III) based on the 3S0 criterion. The method allows the determination of Sb(III) in the range of 5·10‒8 ‒ 1.1·10‒6 g cm–3. The effects of certain foreign ions the reaction rate were determined for an assessment of the selectivity of the method. The kinetic parameters of the reaction were reported, and the rate equations were suggested. The results were validated statistically and through recovery studies. The proposed method has been successfully applied to the determination of Sb(III) in various model and real samples.

scholarly journals A Simple and Sensitive Inhibitory Kinetic Method for the Carbocisteine Determination

2021 ◽  
Vol 66 (1) ◽  
Author(s):  
Abhishek Srivastava ◽  
Vivek Sharma ◽  
Vinay Kumar Singh ◽  
Krishna Srivastava
Keyword(s):  
Good Accuracy ◽  
Quantitative Estimation ◽  
Kinetic Method ◽  
Fixed Time ◽  
Disodium Salt ◽  
Disulfonic Acid ◽  
Stable Complex ◽  
Reaction Conditions ◽  
Kinetic Determination

Abstract. A fast, reproducible, and sensitive method is proposed for the kinetic determination of carbocisteine (CCys). The method depends on the inhibitory property of carbocisteine, which reduces the Hg2+ catalyzed substitution rate of cyanide from [Ru(CN)6]4- with N-R-salt (1-Nitroso-2-naphthol-3,6-disulfonic acid disodium salt) via forming a stable complex with Hg2+. Spectrophotometric measurements were carried out by recording the absorbance at 525 nm (λmax of [Ru(CN)5 Nitroso-R-Salt]3- complex) at a fixed time of 10 and 15 min under the optimized reaction conditions with [N-R-salt] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M and [Ru(CN)64-] = 4.25 × 10-5  M. With the proposed method, CCys can be determined quantitatively down to 3.0 × 10-6 M. This methodology can be effectively used for the rapid quantitative estimation of CCys in the pharmaceutical samples with good accuracy and reproducibility. The addition of common excipients in pharmaceuticals even up to 1000 times with [CCys] does not interfere significantly in the estimation of CCys.   Resumen. Se propone un método rápido, reproducibley sensible para la determinación cinética de la carbocisteina (CCys). El método depende de la propiedad inhibitoria de la carbocisteina que reduce la tasa de sustitución catalizada por Hg2+ del cianuro de [Ru(CN)6]4- con la sal N-R (sal disódica del ácido 1-Nitroso-2-naftol-3,6-disulfónico) mediante la formación de un complejo estable con Hg2+. Las mediciones espectrofotométricas se llevaron a cabo registrando la absorbancia a 525 nm (λmax del complejo [Ru(CN)5 Sal-Nitroso-R]3-) en un tiempo fijo de 10 y 15 min en las condiciones de reacción optimizadas con [sal-NR] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M y [Ru(CN)64-] = 4.25 × 10-5 M. Con el método propuesto, CCys se puede determinar cuantitativamente hasta 3,0 × 10-6 M. Esta metodología se puede utilizar eficazmente para la estimación cuantitativa rápida de CCys en las muestras farmacéuticas con buena precisión y reproducibilidad. La adición de excipientes comunes en productos farmacéuticos incluso hasta 1000 veces con [CCys] no interfiere significativamente en la estimación de CCys.

A Kinetic Method for Characterization of Heterogenous Fibrinogen and Its Application to Fibrinogen Grand Rapids, a Congenital Dysfibrinogenemia

1982 ◽  
Vol 48 (02) ◽  
pp. 182-186 ◽  
Author(s):  
D L Higgins ◽  
S D Lewis ◽  
J A Penner ◽  
J A Shafer
Keyword(s):  
Steady State ◽  
Kinetic Parameter ◽  
Kinetic Analysis ◽  
Kinetic Method ◽  
Plasma Fibrinogen ◽  
Normal Value ◽  
Steady State Kinetic ◽  
Grand Rapids ◽  
State Kinetic

SummaryA kinetic analysis was developed to determine the steady state kinetic parameter kcat/KM for the thrombin-catalyzed release of FPA from abnormal and normal fibrinogen in mixtures of the two. Such mixtures are likely to comprise the fibrinogen of individuals with congenital dysfibrinogenemia. The analysis was used to characterize fibrinogen Grand Rapids, a new congenital dysfibrinogenemia. It indicated that fibrinogen from affected individuals was composed of normal and abnormal fibrinogen in roughly equal amounts, and that the value of kcat/KM for the thrombin-catalyzed release of FPA from the fibrinogen variant was 77fold lower than that for the release of FPA from the normal fibrinogen. In separate studies, fibrinogen Grand Rapids was found to exhibit a reduced clottability. Additionally, affected individuals appeared to have plasma fibrinogen concentrations which were about one-third the normal value.

Automated kinetic determination of angiotensin-converting enzyme in serum.

1984 ◽  
Vol 30 (6) ◽  
pp. 901-902 ◽  
Author(s):  
A Harjanne
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Previous Method ◽  
Converting Enzyme ◽  
Kinetic Determination ◽  
Assay Time ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Abstract In this automated kinetic modification of a previous method (Anal Biochem 95: 540-548, 1979) for determining angiotensin-converting enzyme (EC 3.4.15.1), 3-(2- furylacryloyl )-L- phenylalanylglycylglycine is used as the substrate. The change in absorbance at 340 nm is used to monitor hydrolysis of the substrate. The rate of hydrolysis is roughly threefold greater than with previously reported substrates, so assay time and sensitivity are improved.

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