Iodination of Keratin

Richards, H. R.; Speakman, J. B.

doi:10.1038/171751a0

Cited by 10 publications

(5 citation statements)

References 1 publication

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“…Iodine‐mediated oxidation, a procedure frequently used in the directed disulfide bond formation process , has inherently limited applicability because of the side reactions at methionine , tryptophan , and occasionally tyrosine residues . An iodine‐free directed process would significantly improve the scope of insulin analog synthesis and, more importantly, could be applicable to the preparation of insulin‐like peptides with oxidation sensitive side chains.…”

Section: The Chemical Synthesis Of Insulinmentioning

confidence: 99%

Chemical synthesis of peptides within the insulin superfamily

Liu

Zaykov

Levy

et al. 2016

Journal of Peptide Science

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The synthesis of insulin has inspired fundamental advances in the art of peptide science while simultaneously revealing the structure-function relationship of this centrally important metabolic hormone. This review highlights milestones in the chemical synthesis of insulin that can be divided into two separate approaches: (i) disulfide bond formation driven by protein folding and (ii) chemical reactivity-directed sequential disulfide bond formation. Common to the two approaches are the persistent challenges presented by the hydrophobic nature of the individual A-chain and B-chain and the need for selective disulfide formation under mildly oxidative conditions. The extension and elaboration of these synthetic approaches have been ongoing within the broader insulin superfamily. These structurally similar peptides include the insulin-like growth factors and also the related peptides such as relaxin that signal through G-protein-coupled receptors. After a half-century of advances in insulin chemistry, we have reached a point where synthesis is no longer limiting structural and biological investigation within this family of peptide hormones. The future will increasingly focus on the refinement of structure to meet medicinal purposes that have long been pursued, such as the development of a glucose-sensitive insulin. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

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Section: The Chemical Synthesis Of Insulinmentioning

confidence: 99%

Chemical synthesis of peptides within the insulin superfamily

Liu

Zaykov

Levy

et al. 2016

Journal of Peptide Science

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“…Four further methods aimed at detecting chemical differences in the two segments as well as differences in accessibility to chemical reagents depending on histological features were unsuccessful. Wool stained with (i) ninhydrin by the method of Cockburn, Jagger, and Speakman (1953), (ii) iodine by the method of Richards and Speakman (1953), and (iii) 2 : 4 dinitrofluorobenzene by the method of Middlebrook (1951), and studied in cross sections failed to show segmentation. In the last case, reduction of the DNP-wool with stannous chloride followed by coupling with H-acid produced no change in the staining result and so no localized distribution of side-chain -NH2 groups could be established.…”

Section: (F) Further Experiments To Reveal Segmentation In Wool Cortexmentioning

confidence: 99%

The Bilateral Structure of Wool Cortex and Its Relation to Crimp

Fraser¹,

Rogers²

1955

Aust. Jnl. Of Bio. Sci.

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Xew evidence of the nature of the bilateral cortex in crimped wool is presented and discussed in relation to the physical and chemical properties of the wool fibre. The origin of the asymmetry in the cortex was studied by cutting cross sections of sheep skin and swelling plucked wool roots.It is shown that the bilateral structure is present before the cortex is keratinized and does not originate from an asymmetrical keratinization as has been suggested. Coarse wools, in which crimp is much less, are shown to possess a radial asymmetry in which the peripheral cortical cells are less accessible to basic dyes and have a higher sulphur content than the central cells. This is related to the difference between the curved follicles from which fine fibres are produced and the straighter follicles producing coarse fibres.

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“…Being a fibrous protein, its complex chemical structure consisted of peptide linkages ( Figure 6) having higher contents of tyrosine and glycine residues; the macromolecular chains are disposed in a helical geom etry (αhelix structure). Richards and Speakman [121,122] treated wool with aqueous solutions of iodine in potas sium iodide at different pH values and temperatures. The extent of iodine incorporation into the tyrosine unit was mediumdependent.…”

Section: Iodine-proteinic Fiber Complexesmentioning

confidence: 99%

Molecular iodine/polymer complexes

Moulay

2013

Journal of Polymer Engineering

164

127

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A unique feature of molecular iodine by far, is its ability to bind to polymeric materials. A plethora of natural and synthetic polymers develop complexes when treated with molecular iodine, or with a mixture of mole cular iodine and potassium iodide. Many unexpected findings have been encountered upon complexation of iodine and the polymer skeleton, including the color formation, the polymer morphology changes, the compl exation sites or regions, the biological activity, and the electrical conductivity enhancement of the complexes, with poly iodides (I n¯) , mainly I 3¯ and I 5¯, as the actual binding species. Natural polymers that afford such complexes with iodine species are starch (amylose and amylopectin), chitosan, glycogen, silk, wool, albumin, cellulose, xylan, and natural rubber; iodinestarch being the oldest iodinenatural polymer complex. By contrast, numerous synthetic polymers are prone to make com plexes, including poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), nylons, poly(Schiff base)s, poly aniline, unsaturated polyhydrocarbons (carbon nano tubes, fullerenes C 60 /C 70 , polyacetylene; iodinePVA being the oldest iodinesynthetic polymer complex.

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Iodination of Keratin

Cited by 10 publications

References 1 publication

Chemical synthesis of peptides within the insulin superfamily

Chemical synthesis of peptides within the insulin superfamily

The Bilateral Structure of Wool Cortex and Its Relation to Crimp

Molecular iodine/polymer complexes

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