A total of 0.1 ml of supernatant was added to cuvette containing 1.9 ml of 50mM phosphate buffer (pH 7). The reaction was started by the addition of 1 ml freshly prepared 30mM H2O2. The rate of decomposition of H2O2 was measured spectrophotometrically at 240 nm. Catalase values were expressed as n moles H2O2 consumed/min/mg protein. Measurement of lipid peroxidation TBARS, a measure of lipid per oxidation, was measured as described by Ohkawa .
Standardization of NaOH solution Accurately weigh out a sample of approximately 0.3-0.4 g of primary standard potassium hydrogen phthalate, KHPh, which has been previously dried at 120°C. Do not use more than 0.4 g. To obtain an accurate mass, weigh the sample on weighing paper, slide it into a clean (but not necessarily dry) 250 mL Erlenmeyer flask and reweigh the paper to account for any KHPh that may remain on it. Dissolve the KHPh sample in about 50 mL of CO2-free water and add 2-3 drops of 0.1% phenolphthalein indicator. Begin adding the approximately 0.1 M sodium hydroxide solution from the buret while continuously swirling the flask contents. Do not open the stopcock completely.
The final volume was recorded. A pH probe connected through Microlab was calibrated using buffer solutions of pH 4.00, 7.00, and 10.00. The calibrated pH probe was used in order to measure the pH of the titrated solution of the unknown weak acid. These same steps were repeated except 2 mL of the strong base were titrated into the weak acid solution instead of 4 mL. This process was repeated 10 times.
Upon finding the actual concentrations of salicylic acid, concentration of aspirin in the flask at various times can be found using the equation [aspirin]t = [aspirin]0 – [salicylic acid], since at constant volume, number of moles of initial aspirin decrease to form salicylic acid. Initial concentration of aspirin formed as follows: [aspirin]0 = 0.212g / (180.157gmol-1 * 50/1000 L) = 0.0235 mol L-1. Thus using the first test as sample, [aspirin]t = 0.0235 – 9.981*10-4 = 0.0225 mol L-1. To find the rate constant, we will need to log the value of [aspirin]t and plot it against time to find the rate constant. Figure 1 shows the diluted and actual concentrations of salicylic acid, the concentration and log value of aspirin at various times.
This solution was diluted with diluents to gae a concentration of 0.1 mg/ml solution each of Amoxicillin trihydrate. The HPLC method was applied to the solutions and the results obtained were shown in table 4.6.11. System suitability solution: 25.0 µg/mL each of of USP Amoxicillin RS in Diluent. Precision
The components required for prokaryotic elongation process includes ,the initiation complex described above, aminoacyl-tRNAs, a set of three soluble cytosolic elongation factors (EF-Tu, EF-Ts, and EF-G in bacteria), and GTP. During the first step of elongation cycle the next aminoacyl-tRNA binds to the ribosomal A site. The appropriate aminoacyl-tRNA associates with a complex of GTP-bound EF-Tu resulting in formation of aminoacyltRNA–EF-Tu–GTP complex. It binds to the ribosomal A site with simultaneous hydrolyzed of GTP and an EF-Tu–GDP complex is released from the 70S ribosome. The EF-Tu–GTP complex is then regenerated in a process requiring EF-Ts and GTP.
It aids in the differentiation of species from the genera Corynebacterium, Clostridium, Bacillus, Bacteroides, Fusobacterium and members of Enterococcus . Gelatin hydrolysis test is used to detect the ability of an organism to produce gelatinase (proteolytic enzyme) that liquefy gelatin. This process takes place in two sequential reactions. In the first reaction, gelatinase degrade gelatin to polypeptides. Then, the polypeptides are further converted into amino acids.
In this experiment, racemic 2-methylcyclohexanone was reduced using sodium borohydride as a nucleophile to give a diastereomeric mixture of cis and trans secondary alcohols. The products were analyzed for purity using IR spectroscopy and gas chromatography. 1.2 g of 2-methylcyclohexanone and 10 mL of methanol were combined in a flask and cooled in an ice bath. Two 100 mg portions of sodium borohydride were added to the flask and stirred. 5 mL of 3M sodium hydroxide, 5 mL of de-ionized water, and 15 mL of hexane were added to the reaction flask and stirred.
The reaction was started by adding 0.1 ml of the crude extract to 0.5 ml of the reaction mixture, which contained 7 mm MgCl2, 5 mm Na2MoO4, 2mm Na2-ATP and 0.032 U ml-1 of sulphate-free inorganic pyrophosphate in 80 mm Tris–HCl buffer (pH 8.0). Another aliquot from the same extract was added to the
Linoleic acid peroxidation was initiated by the addition of 4 mM FeSO4.7H2O, incubated for 60 min at 37oC and terminated by the addition of 2 mL of ice cold trichloroacetic acid (10% v/v). An amount of 1 mL of thiobarbituric acid (1% w/v in 50 mM NaOH) was added to 1 mL of the reaction mixture, followed by heating at 95oC for 60 min. The reaction sample was read at 532 nm.7 The percentage of linoleic acid peroxidation inhibition activity was calculated using the following equation: % Inhibition = [(AB - AA)/AB] x 100, where AB, absorption of blank sample, AA, absorption of test sample. 2.5.4. Metal chelating activity Briefly, 2 mM FeCl2 was added to different concentrations of test sample and reaction was initiated by the addition of 5 mM ferrozine.