Use of purified lyophilized human lactate dehydrogenase isoenzymes in a study of the measurement of lactate dehydrogenase activity.

1986 ◽  
Vol 32 (5) ◽  
pp. 758-762 ◽  
Author(s):  
D A Smith ◽  
G C Moses ◽  
A R Henderson
Keyword(s):  
Lactate Dehydrogenase ◽  
Zero Order ◽  
Lactate Dehydrogenase Activity ◽  
First Order ◽  
First Order Kinetics ◽  
Activity Concentrations ◽  
Zero Order Kinetics ◽  
Specific Activities ◽  
The Stability ◽  
Lactate Dehydrogenase Isoenzymes

Abstract We examined the stability of human lactate dehydrogenase (EC 1.1.1.27; LD) isoenzymes 1, 2, and 3--purified to specific activities of about 200 kU/g--when lyophilized in a buffered stabilized matrix of bovine albumin. Each isoenzyme was prepared at two activity concentrations and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. LD-1 activity decayed with zero-order kinetics, LD-2 and LD-3 with first-order kinetics. The extrapolated half-lives of these preparations at -20 degrees C varied between 80 and 530 years. Stability of reconstituted samples stored at 4 degrees C was excellent for LD-1 but poor for LD-2 and LD-3. We suggest that preparations of human LD-1 be further investigated as a possible reference material.

Use of purified lyophilized human lactate dehydrogenase isoenzyme 5 in a study of measuring lactate dehydrogenase activity.

1989 ◽  
Vol 35 (8) ◽  
pp. 1774-1776 ◽  
Author(s):  
D A Smith ◽  
G C Moses ◽  
A R Henderson
Keyword(s):  
Lactate Dehydrogenase ◽  
Half Life ◽  
Specific Activity ◽  
Lactate Dehydrogenase Activity ◽  
Bovine Albumin ◽  
First Order ◽  
First Order Kinetics ◽  
The Stability ◽  
Lactate Dehydrogenase Isoenzymes ◽  
Excellent Stability

Abstract We examined the stability of human lactate dehydrogenase (EC 1.1.1.27) isoenzyme 5--purified to a specific activity of about 400 kU/g--when lyophilized in a buffered, stabilized matrix of bovine albumin. This isoenzyme was prepared with a final activity of about 500 U/L and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. This isoenzyme decayed with approximate first-order kinetics, with an estimated half-life at -20 degrees C of about 475 years. Stability of reconstituted samples stored at 20 or 4 degrees C was poor, suggesting that the reconstituted material should be used without delay; material stored at -20 degrees C showed excellent stability for 15 days. We propose that such preparations might be further investigated as standards for use in electrophoresis of lactate dehydrogenase isoenzymes.

Parameters Effect on Photocatalytic Reduction Kinetics of Bromate in Aqueous Dispersion of TiO2

2013 ◽  
Vol 779-780 ◽  
pp. 1658-1665
Author(s):  
Rong Shu Zhu ◽  
Fei Tian ◽  
Ling Ling Zhang ◽  
Ling Min Yu
Keyword(s):  
Aqueous Dispersion ◽  
Zero Order ◽  
Photocatalytic Reduction ◽  
Reduction Kinetics ◽  
First Order ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
Experimental Parameters ◽  
Pseudo First Order ◽  
Kinetics Of

This paper studied the photocatalytic reduction kinetics of bromate in aqueous dispersion of TiO2 and investigated the effects of experimental parameters, including initial concentration of BrO3-, pH, TiO2 dosage, anion and cation. The results indicate that the process of photocatalytic reduction of bromate follows a zero-order kinetics. In all the investigated experimental parameters, the initial bromate concentration, pH and anion have great effect on the photocatalytic reduction kinetics. The processes of photocatalytic reduction of bromate show the pseudo first-order kinetics at initial bromate concentration of 0.39 μmolL-1, pH=5.0, or in presence of HCO3-/CO32-, NO3-, SO42-, respectively.

Investigations into the kinetics and stoichiometry of bacterial oxidation of covellite (CuS) using a polarographic oxygen probe

1978 ◽  
Vol 24 (8) ◽  
pp. 998-1003 ◽  
Author(s):  
Pamela A. D. Rickard ◽  
Donald G. Vanselow
Keyword(s):  
Oxygen Uptake Rate ◽  
Zero Order ◽  
Bacterial Oxidation ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Cupric Ion ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
Cupric Sulphate ◽  
Kinetics Of

"Oxygraph" apparatus was used to measure quantitatively the kinetics of oxidation of synthetic covellite (CuS) in the presence and absence of Thiobacillus species. The expected stoichiometric relationship between oxygen consumed and cupric sulphate produced was verified by atomic absorption assays of cupric ion and sulphate ion. Thiobacillus cultures markedly increased the oxidation rate.The dependence of each oxygen-uptake rate on oxygen concentration was also measured. Sterile controls and some bacterial cultures showed first-order kinetics while other cultures showed zero-order kinetics.Addition of biological inhibitors to reacting slurries revealed that cultures showing first-order kinetics did not oxidize CuS itself but merely oxidized elemental sulphur formed by non-enzymic oxidation of CuS. Cultures showing zero-order kinetics oxidized CuS in a way that resulted in all oxygen reduction being enzymic. This mechanism possibly involves the cyclic oxidation and reduction of soluble iron.

Ring-Opening Polymerization of ε-Caprolactone Using Novel Tin(II) Alkoxide Initiators

2008 ◽  
Vol 55-57 ◽  
pp. 757-760 ◽  
Author(s):  
A. Kleawkla ◽  
Robert Molloy ◽  
W. Naksata ◽  
Winita Punyodom
Keyword(s):  
Solid State ◽  
Rate Constants ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Zero Order ◽  
Molecular Aggregation ◽  
First Order ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
Kinetics Of

Two novel tin(II) alkoxides, namely: tin(II) hexoxide, Sn(OC6H13)2, and tin(II) octoxide, Sn(OC8H17)2, have been synthesized for use as coordination-insertion initiators in the bulk ring-opening polymerization of ε-caprolactone. The kinetics of the polymerization reactions were studied at 140 °C by dilatometry. It was found that both alkoxides were slow to dissolve in the ε-caprolactone monomer due to their molecular aggregation in the solid state. As a result, the slow solubilization of the initiators gave rise to deviations from the expected first-order kinetics. Instead, the kinetic results adhered more closely to zero-order kinetics with apparent zero-order rate constants k0 of 6.58 x 10-2 and 4.63 x 10-2 mol l-1 min-1 for the hexoxide and octoxide respectively

Nota. Cinética de pardeamiento no enzimático de zumo de pera concentrado Note./ Non-enzymatic browning kinetics of concentrated pear juice

1997 ◽  
Vol 3 (3) ◽  
pp. 213-218 ◽  
Author(s):  
A. Ibarz ◽  
O. Martín ◽  
G.V. Barbosa-Cánovas
Keyword(s):  
Zero Order ◽  
Enzymatic Browning ◽  
First Order ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
Soluble Solid ◽  
Pear Juice ◽  
Kinetics Of

Non-enzymatic browning kinetics of concentrated juice for three pear varieties (Alexandrine Douillard, Flor de Invierno and Blanquilla) was evaluated at three temperatures (90, 80 and 70 °C) and different soluble solid contents (52, 62 and 72 °Brix). The evolution of absorbance at 420 nm is described by zero order kinetics, but the formation of 5-hydroxymethyl-2 furfuraldehyde (HMF) and the reduction in formol index followed first order kinetics. The Alexandrine Douillard juices showed non-enzymatic browning which was less pronounced than in Flor de Invierno and Blanquilla juices.

Sorbate destruction and non-enzymatic browning in model aqueous systems Destruccion de sorbatos y pardeamiento no enzimático en sistemas modelo acuosos

1997 ◽  
Vol 3 (6) ◽  
pp. 405-411 ◽  
Author(s):  
C.A. Campos ◽  
S.M. Alzamora ◽  
L.N. Gerschenson
Keyword(s):  
Citric Acid ◽  
Phosphoric Acid ◽  
Sorbic Acid ◽  
Zero Order ◽  
Model Systems ◽  
Enzymatic Browning ◽  
First Order ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
System Composition

The effect of system composition on sorbate destruction and sensory damage due to non-enzy matic browning was studied in aqueous model systems with a water activity ( aw) of 0.91 and a pH of 5.0-6.0. The rate constants of sorbate destruction could be described by first order kinetics and those from non-enzymatic browning by zero order kinetics. Both reactions were found to be related not only to temperature and pH but also to the humectants (NaCl, glycerol) used to depress aw. A higher preservative retention and a smaller amount of browning was produced by the use of a mixture of 35.0 g/kg of NaCl and 220.0 g/kg of glycerol as a humectant instead of one of them alone, citric acid instead of phosphoric acid as the acidifying agent, and glass flasks instead of polyethylene containers. The non-enzymatic browning reactions were greatly influenced by sorbic acid destruction. The inclusion of glycine was responsible for the enhanced sorbate destruc tion and browning development.

RBC Kinetics in Treating Domestic and Industrial Dairy Wastewater Under Low and High Organic Loading Conditions

1992 ◽  
Vol 27 (4) ◽  
pp. 665-692 ◽  
Author(s):  
Rao Y. Surampalli ◽  
E. Robert Baumann
Keyword(s):  
Zero Order ◽  
Dairy Wastewater ◽  
Organic Load ◽  
Secondary Effluent ◽  
Normal Loading ◽  
First Order ◽  
Substrate Removal ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
Rotating Biological Contactors

Abstract A full-scale, four-stage RBC (rotating biological contactors) plant, having parallel trains used to treat domestic and industrial dairy wastewater, failed to meet standard secondary effluent limits due to overloading in the two initial stages. The plant was first operated under normal loading; subsequently the load to the plant was increased in an incremental fashion by increasing the load from the dairy. This was done to evaluate the effectiveness of the use of supplemental aeration to eliminate oxygen-limiting conditions in the overloaded stages. An enlarged first stage was later created to lower the organic load to the initial stages by removing the wooden baffles between the first and second stages. The experimental work at the plant was conducted for approximately six months, during which daily 24-hour composite samples were collected at the end of each stage and analyzed for various parameters. The experimental results indicated that substrate removal with supplemental air and an enlarged first stage followed first-order kinetics at both lower and higher organic loadings. Without supplemental air, substrate removal followed second-order kinetics at lower loadings and zero-order kinetics at higher organic loadings. With an enlarged first stage only, substrate removal followed first-order kinetics at lower loading and zero-order kinetics at higher loadings. Overall, RBC performance improved significantly with supplemental air and an enlarged first stage. The results also suggest that higher organic loadings and removals can be achieved in the presence of supplemental air due to the maintenance of higher dissolved oxygen levels in the mixed liquor.

scholarly journals The influence of hydrophylic polymers on the release rate of calcium dobesilate in hydrogel formulation assessed in vitro using porcine ear skin

2015 ◽  
Vol 28 (4) ◽  
pp. 225-230 ◽  
Author(s):  
Dorota Wojcik-Pastuszka ◽  
Anna Lisik ◽  
Maria Twarda ◽  
Ryszard Berkowski ◽  
Witold Musial
Keyword(s):  
Release Rate ◽  
Hydroxypropyl Methylcellulose ◽  
Zero Order ◽  
Kinetics Model ◽  
Calcium Dobesilate ◽  
First Order ◽  
Anionic Polymers ◽  
First Order Kinetics ◽  
Zero Order Kinetics

Abstract A shortage of available experimental data exists in the available bibliography on the release rate of calcium dobesilate (CD) from hydrogel formulations. Thus, the aim of the study was to evaluate the effect of selected hydrophilic nonionic polymers and anionic polymers on the release rate of CD from formulation provided for dermal application, as compared to the reference product in the market. The work utilized excised pork skin, while, Methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), and anionic polymers (copolymers of acrylic acid) were used as CD carriers. The release study was executed by the pharmacopoeial paddle method, with extraction cells and fresh excised porcine skin as a membrane. CD in aqueous acceptor fluid was quantified by UV-VIS spectrometry at 300 nm. Subsequently, the kinetic curves were fitted to a zero-order kinetics model, a first-order kinetics model, a second-order kinetics model, as well as to the Higuchi model. The work saw that porcine ear skin influences the release pattern of the CD, compared to the artificial membrane. In the study, the evaluated formulations with MC, polyacrylic acid (PA) and polyacrylate crosspolymer 11 (PC-11) deliver over 60% of the active component (AC), within 250 min, through the excised porcine ear skin, to the acceptor compartment. Moreover, the release observed via porcine ear skin to the aqueous acceptor compartment is congenial to zero-order or first-order kinetics. In addition, the formulations prepared on the basis of MC and PA appear to control AC delivery, independently of actual concentration of AC.

scholarly journals Bleaching of chlorophylls by UV irradiation in vitro: The effects on chlorophyll organization in acetone and n-hexane

2008 ◽  
Vol 73 (3) ◽  
pp. 271-282 ◽  
Author(s):  
Jelena Zvezdanovic ◽  
Dejan Markovic
Keyword(s):  
Uv Irradiation ◽  
Photosynthetic Pigments ◽  
Energy Input ◽  
First Order ◽  
First Order Kinetics ◽  
Uv Photons ◽  
The Stability ◽  
Major Factors

The stability of chlorophylls toward UV irradiation was studied by Vis spectrophotometry in extracts containing mixtures of photosynthetic pigments in acetone and n-hexane. The chlorophylls underwent destruction (bleaching) obeying first-order kinetics. The bleaching was governed by three major factors: the energy input of the UV photons, the concentration of the chlorophylls and the polarity of the solvent, implying different molecular organizations of the chlorophylls in the two solvents.

Improved column method for separating lactate dehydrogenase isoenzymes 1 and 2.

1978 ◽  
Vol 24 (3) ◽  
pp. 480-482 ◽  
Author(s):  
D W Mercer
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Creatine Kinase ◽  
Heart Disease ◽  
Lactate Dehydrogenase ◽  
Sodium Chloride ◽  
Lactate Dehydrogenase Activity ◽  
Column Method ◽  
Creatine Kinase Mb ◽  
Lactate Dehydrogenase Isoenzymes

Abstract Lactate dehydrogenase (LD) isoenzymes 1 and 2 in human serum were separated on a column of diethylaminoethyl-Sephadex. Samples layered on mini-columns were eluted with buffered sodium chloride (100, 150, and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and their isoenzyme content was evaluated by electrophoresis on polyacrylamide gel. Results for column-fractionated LD-1 and LD-2 were expressed in two ways: LD-1/LD-2 ratios and total LD-1 + LD-2 activities. The former is a more specific indicator of myocardial infarction than the latter. Sera from 10 patients with acute myocardial infarction (increased creatine kinease isoenzyme MB activity) exhibited ratios in the range of 0.92 to 1.56, ratios for 10 patients without heart disease (normal creatine kinase MB) ranged from 0.33 to 0.69.

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