The reaction of oxidizing agents with wool. 4. The reactivity of tyrosine

Alexander, Peter; Gough, D.

doi:10.1042/bj0480504

Cited by 37 publications

(15 citation statements)

References 13 publications

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“…Compared with treatments in the absence of salt, wool treated in the salt solutions was not yellowed so much, had lower alkali solubility and weight loss, and had higher fabric bursting strength and fiber strength ( Even with 10% chlorine on the weight of wool, no change in tyrosine or tryptophan was found, although cystine was extensively oxidized. This does not agree with Alexander and Gough [6] who, using Lugg's method, found losses of tyrosine. Chlorine, in the absence of salt, reacted with amino groups, so it was impossible to tell whether peptide bonds had been hydrolyzed during treatment.…”

Section: Reaction O F W Opl Zeath Chlorine In Concentratedcontrasting

confidence: 72%

Reaction of Wool with Oxidizing Agents in Concentrated Salt Solutions

McPhee¹

1960

Textile Research Journal

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Concentrated salt solutions protect wool from oxidative degradation. Oxidizing agents produce a higher degree of shrink resistance in concentrated salt solutions than in the absence of salt. Many oxidations, followed by a reduction, shrinkproof wool when either treatment alone does not.Results support the idea [20, 46] that attack on disulfide bonds is the only primary reaction during chemical shrinkproofing and that attack at some other point of the protein structure need not occur. However, breaking of disulfide bonds is not sufficient in itself to produce shrinkproofing effects, and the exact nature of chemical changes leading to shrinkproofing is unknown. No conclusive evidence has been found to decide whether or not changes in frictional properties are the general cause of shrinkproofing.Evidence is given that, under conditions where swelling is less than in simple aqueous solutions, reaction still occurs throughout wool fibers rather than only at the surface.The results do not agree with theories which suggest that shrinkproofing is due in some way to formation of degraded layers of protein material in wool fibers.

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Section: Reaction O F W Opl Zeath Chlorine In Concentratedcontrasting

confidence: 72%

Reaction of Wool with Oxidizing Agents in Concentrated Salt Solutions

McPhee¹

1960

Textile Research Journal

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“…3,10 However, peracetic acid adequately removed the colour from bloodmeal, with each component of the PAA solution performing a specific function in the overall decolouring and deodorising mechanisms. 13 However, a later study indicated that performic acid also degraded serine, threonine, tyrosine, phenylalanine and histidine, while PAA oxidation resulted in the conversion of all cystine to cysteic acid, with only small losses of tyrosine, phenylalanine and histidine. 11 Consequently, treating proteins with oxidising agents leads to undesired side effects, including modification of amino acid residues, protein hydrolysis or chain cleavage and protein aggregation.…”

Section: Introductionmentioning

confidence: 99%

Changes to amino acid composition of bloodmeal after chemical oxidation

et al. 2015

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Bovine-derived bloodmeal can be decoloured using peracetic acid, extruded and injection moulded into a yellow translucent bioplastic. This plastic has different properties to extruded and injection moulded bloodmeal, in that it does not require sodium sulfite or urea to be extrudable. The effect of oxidation on the physical and chemical characteristics of the proteins during bloodmeal decolouring with PAA was studied by assessing changes in the amino acid profile. Polymer interactions, hydrophilicity and the destruction of cysteine crosslinks were measured indirectly by assessing protein solubility, molecular weight distribution and by synchrotron FT-IR analysis. Increasing peracetic acid concentration resulted in an increased loss of iron due to destruction of the porphyrin groups, increased solubility due to destruction or conversion of aromatic amino acids into hydrophilic groups, destruction of lysine, reduced protein content due to increased salt content in the final product, and a larger amount of smaller protein peptides but with a similar average molecular weight to bloodmeal. Amino acid analysis showed an increase in cysteine content in the product, FTIR of the sulfur groups revealed that these were heavily oxidised, such that some would be unable to participate in disulfide bonds thereby increasing protein solubility.Please do not adjust margins Please do not adjust margins conditions. The most recent investigation into the effect of PAA oxidation on dairy proteins, indicated that the amount of carbonyl groups increased while thiol (SH) groups decreased; tryptophan and methionine were most vulnerable to oxidation while lysine was not affected. 7 Neither peptide cleavage, nor

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“…'keratose') is based on the methods described by Alexander et al and Widra [49][50][51]. 'keratose') is based on the methods described by Alexander et al and Widra [49][50][51].…”

Section: Preparation Of Keratosesmentioning

confidence: 99%

“…'keratose') is based on the methods described by Alexander et al and Widra [49][50][51]. Losses during acidic oxidation have been shown to be less than 5% [49]. The oxidant first reacts with the cuticle, thereby disrupting the structure FIGURE 6.3 Scanning electron micrograph of a human hair that has been oxidized and treated with 100 mM tris base solution.…”

Section: Preparation Of Keratosesmentioning

confidence: 99%

Keratin

Dyke

2016

Biomaterials From Nature for Advanced Devices and Therapies

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The reaction of oxidizing agents with wool. 4. The reactivity of tyrosine

Cited by 37 publications

References 13 publications

Reaction of Wool with Oxidizing Agents in Concentrated Salt Solutions

Reaction of Wool with Oxidizing Agents in Concentrated Salt Solutions

Changes to amino acid composition of bloodmeal after chemical oxidation

Keratin

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