scholarly journals PHYSICOCHEMICAL PROPERTIES OF THE PROTEOLYTIC ENZYME FROM THE LATEX OF THE MILKWEED, ASCLEPIAS SPECIOSA TORR. SOME COMPARISONS WITH OTHER PROTEASES

1940 ◽  
Vol 23 (3) ◽  
pp. 301-308 ◽  
Author(s):  
Theodore Winnick ◽  
Alva R. Davis ◽  
David M. Greenberg
Keyword(s):  
Physicochemical Properties ◽  
Proteolytic Enzyme ◽  
Arrhenius Equation ◽  
Protein Denaturation ◽  
Order Reaction ◽  
Order Equation ◽  
Heat Inactivation ◽  
First Order ◽  
Different Temperatures ◽  
Asclepias Speciosa

1. The rates of heat inactivation of papain, bromelin, and asclepain were determined at several different temperatures. Papain was by far the most resistant to heat. 2. The destruction of papain at 75–83° and bromelin at 55–70° followed the course of a first order reaction, except that for longer times of heating, bromelin (at 60–70°) was inactivated more rapidly than the first order equation required. 3. The rate of inactivation of asclepain at 55–70° followed the second order equation. 4. The critical thermal increments of inactivation of papain and bromelin, calculated with the van't Hoff-Arrhenius equation, were of the same high order that has been found for protein denaturation. The increment for asclepain was somewhat lower.

Studies in the Vulcanization of Rubber. III—Kinetics of Vulcanization of Rubber with Sulfur and Selenium

1930 ◽  
Vol 3 (4) ◽  
pp. 650-659
Author(s):  
John T. Blake
Keyword(s):  
Molecular Weight ◽  
Order Reaction ◽  
Order Equation ◽  
Second Order Reaction ◽  
Experimental Conditions ◽  
Mathematical Basis ◽  
First Order ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization

Abstract A procedure for the determination of combined selenium in rubber has been evolved. The rate of combination of selenium and rubber has been ascertained under certain conditions and shown to follow a first-order equation. A minimum value for the molecular weight of rubber has been estimated. The formation of hard rubber under chosen experimental conditions has been put on a mathematical basis and has been shown to follow a second-order reaction. The soft- and hard-rubber reactions have been shown qualitatively to be successive reactions and the function of accelerators has been discussed. The theory explains the anomalous results obtained by previous investigators.

scholarly journals Kinetika Reaksi Penurunan Kafein dan Asam Klorogenat Biji Kopi Robusta melalui Pengukusan Sistem Tertutup

2018 ◽  
Vol 38 (1) ◽  
pp. 105
Author(s):  
Sapto Kuncoro ◽  
Lilik Sutiarso ◽  
Joko Nugroho Wahyu Karyadi ◽  
Rudiati Evi Masithoh
Keyword(s):  
Chlorogenic Acid ◽  
Arrhenius Equation ◽  
Order Reaction ◽  
First Order Reaction ◽  
Chlorogenic Acids ◽  
First Order ◽  
Robusta Coffee ◽  
Coffee Beans ◽  
Energy Activation ◽  
Acid Reduction

This study was aimed to examine the correlation between temperature and duration of steaming on caffeine and chlorogenic acid reduction as well as to determine energy activation (Ea) according to Arrhenius equation. About 750 g of Robusta coffee was steamed by autoclaving at 100, 110, 120 °C for 1, 2, 3, 4, 5, 6 and 7 hours. The study was conducted in 3 replications. Analyses of caffeine and chlorogenic acid were performed using HPLC.  Steaming coffee beans at 100, 110 and 120 °C resulted in the highest decrease of caffeine and chlorogenic acids content for 7 hours by 13%, 18% and 25% for caffeine; and by 37%, 50% and 59% for chlorogenic acids. At all temperatures investigated, decaffeination and chlorogenic acid reduction followed first order reaction. The decaffeination equation at 100 °C, 110 °C and  120 °C followed equation of  y = -0.019x + 0.862, y = -0.023x + 0.820, and y = -0.033x + 0.759, respectively. Meanwhile, the chlorogenic acid reduction at 100 °C, 110 °C,  and 120 °C followed equation of y = -0.071x + 1.421, y = -0.089x + 1.271, and y = -0.120x + 1.201. Activation energies of decaffeination and chlorogenic acid reduction were 33,543.66 kJ/mol K and 31,934.91 kJ/mol K, respectively. ABSTRAKPenelitian ini bertujuan untuk mengkaji hubungan antara suhu dan lama pengukusan terhadap penurunan kandungan kafein dan asam klorogenat serta menentukan energi aktivasi (Ea) dengan pendekatan persamaan Arrhenius. Biji kopi Robusta masing-masing seberat 750 g dikukus dalam autoklaf (sistem tertutup) pada suhu 100, 110, dan 120 °C masing-masing selama 1, 2, 3, 4, 5, 6, dan 7 jam. Penelitian dilakukan dengan 3 kali ulangan. Analisis kafein dan asam klorogenat dilakukan menggunakan HPLC. Pengukusan biji kopi pada suhu 100, 110, dan 120 °C, menghasilkan penurunan kandungan kafein dan asam klorogenat tertinggi pada pengukusan selama 7 jam. Penurunan kandungan kafein selama 7 jam pada suhu pengukusan 100, 110, dan 120 °C berturut-turut 13%, 18%, dan 25%. Kandungan asam klorogenat mengalami penurunan 37%, 50%, dan 59% berturut-turut pada suhu 100, 110, dan 120 °C.  Pada semua suhu yang diuji, penurunan kafein dan asam klorogenat mengikuti reaksi orde satu. Penurunan kafein mengikuti persamaan y = -0,019x + 0,862,  y = -0,023x + 0,820, dan y = -0,033x + 0,759, sedangkan untuk asam klorogenat mengikuti persamaan y = -0,071x + 1,421,  y = -0,089x + 1,271, dan y = -0,120x + 1,201. Besarnya energi aktivasi penurunan kafein dan asam klorogenat berturut turut adalah 33.543,66 kJ/molK dan 31.934,91 kJ/Mok.

scholarly journals STUDIES ON A SARCOSINE OXIDASE OF BACTERIAL ORIGIN

1950 ◽  
Vol 34 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Paul H. Kopper ◽  
Keyword(s):  
Chemical Compounds ◽  
Enzyme Concentration ◽  
Order Reaction ◽  
Effect Of Temperature ◽  
Heat Inactivation ◽  
Sarcosine Oxidase ◽  
First Order ◽  
Optimal Activity ◽  
Relationship Of ◽  
The Relationship

A "sarcosine oxidase" was prepared from a creatinine-decomposing strain of Pseudomonas aeruginosa. The enzyme is inactivated by drying, lyophilization, and dialysis against distilled water. No dialyzable cofactor was found. Optimal activity of the enzyme is reached at pH 7.8. Enzyme activity is directly proportional to enzyme concentration and also to substrate concentration up to the point of saturation of enzyme with substrate molecules. One molecule of enzyme combines with one molecule of substrate. Data concerning the effect of temperature and of a variety of chemical compounds on the enzyme are presented. Its inactivation by heat follows the course of a first order reaction, and the critical thermal increment between 48° and 52°C. was calculated to be 103,000 calories per mol. The relationship of enzyme concentration to heat inactivation rates is illustrated.

scholarly journals Kinetic Study of Thermal De-Chlorination of PVC-Containing Waste

2012 ◽  
Vol 730-732 ◽  
pp. 611-616 ◽  
Author(s):  
Alexandra Castro ◽  
Cândida Vilarinho ◽  
Delfim Soares ◽  
Fernando Castro
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Treatment ◽  
Kinetic Model ◽  
Energy Recovery ◽  
Order Reaction ◽  
Pyrolysis Process ◽  
First Order ◽  
Different Temperatures ◽  
The One

The presence of organic compounds on wastes, especially plastics, is considered an important source of energy. However, most of these plastics contain polyvinyl chloride (PVC), causing recycling problems when it is considered a thermal valorization process for its treatment [1], preventing the use of those residues on these processes, which main goal is the energy recovery [2,3]. A possible solution is to remove the chlorine from PVC containing waste through a pyrolysis process before being subjected to a thermal treatment, for energetic valorization. In this work, it was developed a kinetic model for the thermal decomposition of PVC, in view of its de-chlorination. DTA/TGA testing were performed at different temperatures (between the range of decomposition temperatures of the PVC molecule) indicated a first order reaction and an activation energy of 133800 J/mol, value very close to the one obtained in others works reported [4]. A factorial plan was carried out with different temperatures, performed in lab scale, in which best results were obtained at the temperature of 340 °C, proving the kinetic model obtained.

scholarly journals Stability of vitamin C in broccoli at different storage conditions

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Nasser Al-Habsi ◽  
Sithara Suresh ◽  
Amani Al-Yhmedi ◽  
Marwa Al-Shoryani ◽  
Mostafa I. Waly ◽  
...  
Keyword(s):  
Activation Energy ◽  
Vitamin C ◽  
Reaction Rate ◽  
Storage Conditions ◽  
Order Reaction ◽  
Titration Method ◽  
First Order ◽  
Reaction Rate Constants ◽  
Different Temperatures ◽  
Thermal Stability Of

In this study, the retention of vitamin C in fresh broccoli stored at different temperatures (i.e. chiller, room, cooking, and roasting or baking; 5-120°C) was investigated. The thermal stability of vitamin C in broccoli was analysed at 5, 20, 45, 60, 70, 80, 110, and 120°C. The vitamin C content was measured by the indophenol titration method. Vitamin C was affected negatively at all stored temperatures. The degradation of vitamin C was modelled by first-order reaction kinetics and the reaction rate constants were observed as 9.03×10-8 and 5.65×10-3 s-1 when stored at 5°C and 120°C, respectively. The activation energy was estimated as 74.2 kJ/mol within the temperature range used in this study. The lowest decay of vitamin C was observed during the chilling condition. The data on retention of vitamin C in broccoli could be used to determine their stability, when stored as raw, and when heated at different temperatures.

scholarly journals PHYSICOCHEMICAL PROPERTIES OF THE PROTEOLYTIC ENZYME FROM THE LATEX OF THE MILKWEED, ASCLEPIAS SPECIOSA TORR. SOME COMPARISONS WITH OTHER PROTEASES

1940 ◽  
Vol 23 (3) ◽  
pp. 275-288 ◽  
Author(s):  
Theodore Winnick ◽  
Alva R. Davis ◽  
David M. Greenberg
Keyword(s):  
Physicochemical Properties ◽  
Proteolytic Activity ◽  
Proteolytic Enzyme ◽  
Chemical Diffusion ◽  
Urea Solution ◽  
Optimum Temperature ◽  
Asclepias Speciosa ◽  
Clot Blood

1. A study has been made of the properties of a hitherto unreported proteolytic enzyme from the latex of the milkweed, Asclepias speciosa. The new protease has been named asclepain by the authors. 2. The results of chemical, diffusion, and denaturation tests indicate that asclepain is a protein. 3. Like papain, asclepain dots milk and digests most proteins, particularly if they are dissolved in concentrated urea solution. Unlike papain, asclepain did not clot blood. 4. The activation and inhibition phenomena of asclepain resemble those of papain, and seem best explained on the assumption that free sulfhydryl in the enzyme is necessary for proteolytic activity. The sulfhydryl of asclepain appears more labile than that of papain. 5. The measurement of pH-activity curves of asclepain on casein, ovalbumin, hemoglobin, edestin, and ovovitellin showed no definite digestion maxima for most of the undenatured proteins, while in urea solution there were well defined maxima near pH 7.0. Native hemoglobin and ovovitellin were especially undigestible, while native casein was rapidly attacked. 6. Temperature-activity curves were determined for asclepain on hemoglobin, casein, and milk solutions. The optimum temperature was shown to increase with decreasing time of digestion.

Saccharomyces cerevisiae Thermal Inactivation Kinetics Combined with Ultrasound

1999 ◽  
Vol 62 (10) ◽  
pp. 1215-1217 ◽  
Author(s):  
A. LÓPEZ-MALO ◽  
S. GUERRERO ◽  
S. M. ALZAMORA
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Thermal Inactivation ◽  
Order Reaction ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Thermal Treatments ◽  
Combined Treatments ◽  
First Order ◽  
D Values ◽  
Kinetics Of

Inactivation kinetics of Saccharomyces cerevisiae during thermal treatments at moderate temperatures (45.0, 47.5, 50.0, 52.5, or 55.0°C) combined with application of 20 kHz of ultrasound were evaluated. S. cerevisiae inactivation under the combined effects of heat and ultrasound followed first-order reaction kinetics, with decimal reduction times (D) that varied from 22.3 to 0.8 min. D values in treatments that combined heat and ultrasound were significantly smaller (P < 0.05) than D values obtained for thermal treatments and were more noticeable at temperatures below 50°C. The dependence of the D value on temperature had a significantly (P < 0.05) greater z value for combined treatments. Yeast heat inactivation kinetics revealed decreased thermal resistance caused by ultrasound.

PHYSICOCHEMICAL PROPERTIES OF PHAGES FOR AGROBACTERIUM RADIOBACTER

1963 ◽  
Vol 9 (2) ◽  
pp. 199-209 ◽  
Author(s):  
E. B. Roslycky ◽  
O. N. Allen ◽  
Elizabeth McCoy
Keyword(s):  
Physicochemical Properties ◽  
Order Reaction ◽  
Nutrient Broth ◽  
Ph Stability ◽  
First Order Reaction ◽  
Distilled Water ◽  
Water Protection ◽  
Agrobacterium Radiobacter ◽  
Stability Range ◽  
First Order

Plaques of phages PR-1001, PS-192, PR-590a, and PsR-1012 were clear, without halos, and with definite edges. Phage heads were approximately 60 mμ in diameter with short blunt tails. Phage titers in nutrient broth were stable during 452 days storage at 4 °C but were decreased considerably at 25 °C. After 46 days at 37 °C no surviving particles of any of the phages were detected. Ultraviolet inactivation of particles was not a first-order reaction. The pH stability range was between pH 7 and 11. Inactivation at 50 °C and 55 °C was least in saline, more marked in nutrient broth, and most severe in distilled water. Protection against inactivation was a function of the mono- and di-valent cation concentration. Separately the cations provided insignificant protection. NH4+ in combination with Ca++ or Mg++ inactivated phage particles as did also Cu++, Hg++, Al+++, and Fe+++ in solutions of NaCl. Heat-inactivated particles showed collapsed heads that indicated a loss in DNA.

scholarly journals Permanganatic oxidation of neomycine sulphate salt in basic media: a kinetic study

2019 ◽  
Vol 9 (1) ◽  
pp. 159-164
Author(s):  
Narayan V. Lawale ◽  
Bhagwan Singh Dobhal ◽  
Sandip Singh Gaur ◽  
Rajendra Pardeshi
Keyword(s):  
Kinetic Study ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pseudo First Order Reaction ◽  
Reaction Conditions ◽  
First Order ◽  
Alkaline Permanganate ◽  
Different Temperatures ◽  
Alkaline Conditions ◽  
Pseudo First Order

Permanganatic oxidation of Neomycine sulphate salt has been studied at different temperatures using spectrophotometer under alkaline conditions. The effect of variation of substrate Neomycine sulphate salt (NS), oxidant (KMnO4) and NaOH was studied under pseudo first order reaction conditions. The effect of different salts and solvents on oxidation of NS was also studied. The reaction was found to be first order with respect to oxidant, substrate and NaOH.. Keywords: Neomycine sulphate salt (NS), KMnO4 , permanganatic  oxidation, alkaline permanganate

scholarly journals Kinetic and Mechanism of Uncatalytic Oxidation of Dl-Threonine by Cerium (Iv) in Aqueous Acid Medium

2021 ◽  
pp. 51-63
Author(s):  
Gajanand Sahu ◽  
Sanjay Ghosh
Keyword(s):  
Thermodynamic Parameters ◽  
Acid Medium ◽  
Rate Constant ◽  
Acidic Medium ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Aqueous Acid ◽  
Rate Of Reaction ◽  
Different Temperatures

Kinetic of uncatalyzed oxidation of DL-Threonine has been studied by Ce (IV) in acidic medium has been investigatigated by spectrophotometer technique.  The rate of reaction determined at three different temperatures ranging from 298 K to 318 K at the interval of 10 K. The reaction has been found to be a first order reaction in presence or in absence of KCl, CTAB, and SDS. The rate constant, decreases with increasing the concentration of [HSO4-] and [H+] ion. The various thermodynamic parameters were calculated at 298 K, 308 K and 318 K. The proposed mechanism and results is discussed.

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