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Methods for Sequence Determination
Published in Roger L. Lundblad, Chemical Reagents for Protein Modification, 2020
Smithies et al.64 recommend hydrolysis of the thiazolinones or PTHs in 57% hydriodic acid (HI) at 127°C for 20 h. PTH-alanine, -serine, -carboxymethylcysteine, or -cysteine all hydrolyze to alanine. Threonine is identified as a-aminobutyric acid. PTH-tryptophan gives glycine plus alanine, and methionine is destroyed. Alkaline hydrolysis in 0.2 M NaOH plus 0.1 M sodium dithionite allows recovery of methionine and tryptophan and differentiation of alanine from serine or cysteine.
Chemistry and Isotopes of Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
Hydrogen iodide (HI) is a colorless gas that is decomposed by light. It is very soluble in H2O, and the resulting acid (hydriodic acid, HI) is the strongest among all hydrohalic acids. Hydriodic acid is used as a reducing agent. Since the preparation of this compound takes place under fairly drastic laboratory conditions,2 the chances of HI forming during protein iodination seem quite remote.
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
The heterogeneous exchange reaction R–H + I–I* = R–I* + HI has a theoretical maximum of 50% utilization of iodine. In the presence of oxidizing agents such as iodic acid, persulfate, hydriodic acid, or alkaline medium, iodine is consumed and the iodination reaction proceeds to the right. Radioiodine solution for protein labeling should not contain any stabilizer (for example, a reducing agent like sodium bisulfite) because the reducing agent might consume the active species and reduce the yield of radioiodination. Reductant-free radioiodide is commercially available, or it can be produced readily by adding a small amount of iodide carrier and hydrogen peroxide, acidifying, and distilling the iodine into dilute alkali in a glove box or a well-ventilated hood.
Clinical toxicology of exposures to chemicals from clandestine drug laboratories: a literature review
Published in Clinical Toxicology, 2022
Arjen Koppen, Anja P. G. Wijnands-Kleukers, Femke M. J. Gresnigt, Dylan W. de Lange
Hazardous substances may also be formed during drug synthesis. First, the end products themselves may pose health risks, for instance when clandestine drug laboratories are abandoned and new residents are exposed to remaining drug residues [5,9]. Second, several hazardous substances may be formed during the synthesis of illicit drugs. Phosphine is a possible byproduct during the synthesis of metamfetamine via the ephedrine/hydriodic acid/red phosphorus method. Experimental studies mimicking metamfetamine synthesis in clandestine drug laboratories showed that relative high phosphine concentrations could be reached during the “cooking process” [5].