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Methods of Protein Iodination
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
The basic events that take place in an electrolytic cell are illustrated in Figure 30. When direct current is applied, in excess of the decomposition voltage, to a cell containing an aqueous solution of KI, potassium ions move to the cathode and iodide ions to the anode. The anode half-reaction is as follows:
Principles of Radioiodination and Iodine-Labeled Tracers in Biomedical Investigation †
Published in Garimella V. S. Rayudu, Lelio G. Colombetti, Radiotracers for Medical Applications, 2019
Mrinal K. Dewanjee, Shyam A. Rao
Instead of using chemical oxidants, Pennisi and Rosa82 performed electrolysis at a constant current level to convert iodide to iodine for the radioiodination of insulin and other proteins. The procedure is mild and a labeling efficiency of between 30 and 80% has been reported. The electrolytic cell (Figure 12) has a 10-mℓ platinum crucible as the anode, and the platinum cathode (diameter 0.8 to 1.0 mm) is surrounded by a dialyzing cellophane membrane. The crucible contains the solution of the protein to be radioiodinated, along with the radioiodide in isotonic saline solution. A slow and controlled rate of electrolysis results in a steady liberation of radioiodine and thus intrinsically leads to an even distribution of radioiodine among the protein molecules. In the chemical oxidation method, a reactive species of radioiodine is formed instantaneously. In a typical electrolytic radioiodination, 10 to 50 mg of a protein in isotonic saline are mixed with 1 to 5 mCi of radioiodide and are electrolyzed for between 30 and 60 min in a platinum crucible as the anode and a platinum cathode in a small dialysis chamber with a constant current of 6 to 12 μA. The original method83 was modified to perform iodination at a microlevel (1 to 5 μg of protein). The free radioiodide is separated by conventional procedure. The labeled material retains high levels of immunologic and biological activity. The inherent advantages of the technique are that no chemical oxidant or reductant is used and that the substitution level can be controlled by the amount of current or carrier iodide. The disadvantages are the lower specific activity, prolonged exposure of protein to radioiodide, and protein denaturing from dilution and temperature of the electrolysis.
Inactivation of Pseudomonas aeruginosa biofilms formed under high shear stress on various hydrophilic and hydrophobic surfaces by a continuous flow of ozonated water
Published in Biofouling, 2018
Evgenya S. Shelobolina, Diane K. Walker, Albert E. Parker, Dorian V. Lust, Johanna M. Schultz, Grace E. Dickerman
Ozone was generated electrochemically using an electrolytic cell composed of a diamond coated anode, solid phase electrolyte, and stainless steel cathode sandwiched together (Meas et al. 2011). Two, 5 or 7 ppm ozone concentrations were tested. Reverse osmosis (R/O) water was run through the electrochemical cell and dissolved ozone was maintained at the targeted concentration (± 0.5 ppm) in a mixing beaker by adjusting the current on the cell power supply. The mixing beaker contents were continuously recirculated through the ozone generator. As the contents were pumped out for treatment application, an equal amount of R/O water was added back to the beaker. A separate loop served to hydrate the cathode (Figure 3).