Iodide Atoms Research Articles

Radiolysis of vinyl iodide. Part 2.—Solutions of vinyl iodide in carbon tetrachloride

Radiolysis of solutions of vinyl iodide in carbon tetrachloride enables a mechanism of formation of products to be specified. Ethylene is formed within spurs in reactions involving vinyl radicals and hydrogen iodide, while acetylene is formed in three different processes involving molecular decomposition of vinyl iodide, and hydrogen-abstraction reactions by either iodide or chlorine atoms from vinyl radicals. Hydrogen iodide is formed in hydrogen-abstraction reaction by atomic iodine from vinyl radical. Hydrogen is formed in the molecular decomposition and by hot hydrogen atom abstraction. Hydrogen chloride is formed mainly by hot chlorine atom abstraction of hydrogen from vinyl iodide. Competition between the dissociative electron attachment processes of CCl4 and C2H3I strongly affects the hydrogen chloride formation. Vinyl chloride is formed within spurs in reactions involving vinyl radicals and HCl or Cl atoms. There is no evidence of electronic excitation transfer in the present system, and charge transfer seems improbable.

Iodation enzymatique de protéines

AbstractAn iodination enzymatic method has been studied which makes possible the preparation of 125I or 131I labelled proteins.Iodide oxidation is catalyzed by horse‐radish peroxydase; H2O2 is furnished by another enzymatic system: glucose‐glucose oxydase. We have studied: The optimal enzymatic iodination conditions for various proteins with different biological activities (immunological, hormonal, enzymatic). The enzymatic iodination reaction mechanism. Some molecular characteristics of the iodoproteins prepared. We have established that: The iodide oxidation is catalized by the horse‐radish peroxydase and not directly caused by H2O2 produced by the glucose‐glucose oxydase system. When iodide atoms are introduced in a protein in the conditions defined above — serumalbumin or thyroglobulin, for instance — no apparent denaturation occurs; but a shift of the sedimentation coefficient established by sucrose gradient ultra‐centrifugation appears which may be due to a change of the proteins shape. These results has been discussed: as to the validity of this method from a preparative point of view. as a simple model of the physiological structural transitions observed during the biosynthesis and iodination of thyroglobulin.