Purification and kinetic studies of the hemolysin from Escherichia coli

1971 ◽  
Vol 17 (6) ◽  
pp. 741-745 ◽  
Author(s):  
Peter Zwadyk Jr. ◽  
I. S. Snyder
Keyword(s):  
Escherichia Coli ◽  
Ammonium Sulfate ◽  
Reaction Rate ◽  
Kinetic Studies ◽  
Ammonium Sulfate Precipitation ◽  
Complex Curve ◽  
Sheep Erythrocytes

The hemolysin of Escherichia coli has been concentrated 23-fold by ethanol and ammonium sulfate precipitation. Further evidence has been presented that the hemolysin is a protein or peptide. Kinetic studies of the hemolytic reaction reveal a complex curve which consists of a lag, an area of accelerated reaction rate, and a plateau. Kinetic studies also show that the hemolytic reaction can be best demonstrated at a pH of 7.9 and a temperature of 30 °C using a 1% suspension of sheep erythrocytes.

scholarly journals Kinetic studies with the use of proton-magnetic-resonance spectroscopy of the specific α-deuteration of amino acids by Escherichia coli aspartate aminotransferase

1978 ◽  
Vol 171 (3) ◽  
pp. 719-723 ◽  
Author(s):  
E Gout ◽  
S Chesne ◽  
C G Beguin ◽  
J Pelmont
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Aspartate Aminotransferase ◽  
Proton Magnetic Resonance ◽  
Reaction Rate ◽  
Kinetic Studies ◽  
Bond Breaking ◽  
Resonance Spectroscopy ◽  
First Order ◽  
Reaction Rate Constants

Escherichia coli aspartate aminotransferase was exposed to aspartate or phenylalanine without oxo acid in buffered 2H2O. The alpha-hydrogen of the amino acids underwent first-order exchange with respect to both substrate and enzyme. P.m.r. spectroscopy gave consistent reaction-rate constants. The deuterium-exchange rate was only moderately increased by addition of oxo acids and was of the same order as the transamination rate. No beta-deuteration was observed. The C(alpha)-H-bond-breaking step is discussed as a part of the entire transamination mechanism.

Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.)

2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe
Keyword(s):  
Molecular Weight ◽  
Protein Content ◽  
Ammonium Sulfate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Protease Activity ◽  
Protein Concentration ◽  
Temperature Stability ◽  
Partial Purification ◽  
Ammonium Sulfate Precipitation

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 

scholarly journals Structural and Kinetic Studies of Induced Fit in Xylulose Kinase from Escherichia coli

2007 ◽  
Vol 365 (3) ◽  
pp. 783-798 ◽  
Author(s):  
Eric Di Luccio ◽  
Barbara Petschacher ◽  
Jennifer Voegtli ◽  
Hui-Ting Chou ◽  
Henning Stahlberg ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Kinetic Studies ◽  
Induced Fit ◽  
Xylulose Kinase

scholarly journals A set of simple methods for detection and extraction of laminarinase

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ananthamurthy Koteshwara ◽  
Nancy V. Philip ◽  
Jesil Mathew Aranjani ◽  
Raghu Chandrashekhar Hariharapura ◽  
Subrahmanyam Volety Mallikarjuna
Keyword(s):  
Ammonium Sulfate ◽  
Ammonium Sulphate ◽  
Gold Standard ◽  
Direct Detection ◽  
Low Cost ◽  
Direct Analysis ◽  
Reducing Sugar ◽  
Ammonium Sulfate Precipitation ◽  
Simple Method ◽  
Functional Step

AbstractA carefully designed ammonium sulfate precipitation will simplify extraction of proteins and is considered to be a gold standard among various precipitation methods. Therefore, optimization of ammonium sulfate precipitation can be an important functional step in protein purification. The presence of high amounts of ammonium sulphate precludes direct detection of many enzymatically active proteins including reducing sugar assays (e.g. Nelson-Somogyi, Reissig and 3,5-dinitrosalicylic acid methods) for assessing carbohydrases (e.g. laminarinase (β (1–3)-glucanohydrolase), cellulases and chitinases). In this study, a simple method was developed using laminarin infused agarose plate for the direct analysis of the ammonium sulphate precipitates from Streptomyces rimosus AFM-1. The developed method is simple and convenient that can give accurate results even in presence of ammonium sulfate in the crude precipitates. Laminarin is a translucent substrate requiring the use of a stain to visualize the zones of hydrolysis in a plate assay. A very low-cost and locally available fluorescent optical fabric brightener Tinopal CBS-X has been used as a stain to detect the zones of hydrolysis. We also report simple methods to prepare colloidal chitin and cell free supernatant in this manuscript.

Preparation of Human Immunoglobulin by Ammonium Sulfate Precipitation

Vox Sanguinis ◽  
1976 ◽  
Vol 31 (6) ◽  
pp. 423-434
Author(s):  
A.F.S.A. Habeeb ◽  
Robert D. Francis
Keyword(s):  
Ammonium Sulfate ◽  
Human Immunoglobulin ◽  
Ammonium Sulfate Precipitation

Photocatalytic Degradation of Methyl Orange by TiO2/Schorl Photocatalyst: Kinetics and Thermodynamics

2015 ◽  
Vol 713-715 ◽  
pp. 2789-2792
Author(s):  
Huan Yan Xu ◽  
Xue Li ◽  
Yan Li ◽  
Ping Li ◽  
Wei Chao Liu
Keyword(s):  
Methyl Orange ◽  
Reaction Rate ◽  
Reaction Kinetic ◽  
Kinetic Studies ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Solution Ph ◽  
Kinetics And Thermodynamics ◽  
Hoff Equation ◽  
Degradation Of Methyl Orange

An active dye, Methyl Orange (MO) was employed as the target pollutant to evaluate the photocatalytic activity of TiO2/schorl composite and the kinetics and thermodynamics of this process was emphasized in this work. Langmuir–Hinshelwood kinetic model was employed for the kinetic studies and the results revealed that the process of MO photocatalytic discoloration by TiO2/schorl composite followed one order reaction kinetic equation under different conditions. The reaction rate constant (k) increased with initial MO concentration decreasing. When the catalyst dosage or solution pH increased,kvalues increased and then decreased. The possible reasons for these phenomena were discussed. Finally, the thermodynamic parameters ΔG, ΔH, ΔSwere obtained by the classical Van't Hoff equation.

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