The Influence of Alkali Treatment on Native and Denatured Proteins

Mellet, Philippe

doi:10.1177/004051756803801001

Cited by 13 publications

(8 citation statements)

References 28 publications

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“…Hot alkali treatment of proteins is known to degrade the amino acids cystine (Cys) 2 , lysine (Lys), and serine (Ser), threonine (Thr), and arginine (Arg). (Cys) 2, Lys, and Arg are main participants in the formation of lanthionine, lysinoalanine, and ornithine [18]. Initially strong aqueous alkali can decompose aliphatic disulfides by direct attack of hydroxide ion on sulfur to give thiol (cysteine) and sulfonic acid (cysteic acid residues) as the principal products [19].…”

Section: Keratin Hydrolysate Formationmentioning

confidence: 99%

Enzyme-mediated Crosslinking of Wool. Part II: Keratin and Transglutaminase

Cardamone

Phillips

2007

Textile Research Journal

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Keratin hydrolysates (KH) and their lyophilized powders (KP) were applied with transglutaminase (amine γ-glutamyltransferase EC 2.3.2.13; TG) to fine jersey wool fabric bleached by peroxycarboximidic acid in the first step of the ARS process. The full ARS process involving treatment with proteolytic enzyme (Esperase 8.0L™) after pretreatment by bleaching can result in up to 18% fabric strength loss in fine-gage jersey knits, yet the ARS process has met with industry acceptance. To alleviate strength loss we applied solutions of KH and KP in combination with TG as a transferase enzyme to catalyze transamidation reactions involving keratin as KH and KP and keratinaceous wool fabric in order to provide crosslinking between and among these keratin constituents. Treatments of KH from 100% to 10% owb with TG showed that shrinkage could be controlled; application of 6% owf KP and 2% owf TG controlled shrinkage to 4.89%. Scanning electron micrographs showed that the keratin material coated the fibers to fill the raised scales of the wool. The results of statistical analysis predicted the optimum application conditions of 5% KP and 5% TG. These conditions minimized felting shrinkage to 5.21% and fabric weight change to 0.26% and maximized dry burst strength to 4.7% loss and increase in fabric whiteness to 17.8 whiteness index units. Wool material, including hydrolysates and powders crosslinked by TG enzyme mediation can provide a rich resource for the production of modified keratin-based biomaterials.

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Section: Keratin Hydrolysate Formationmentioning

confidence: 99%

Enzyme-mediated Crosslinking of Wool. Part II: Keratin and Transglutaminase

Cardamone

Phillips

2007

Textile Research Journal

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“…oxidative scission of the dehydroalanine derivative followed by oxidation. Later, Mellet (1968) also demonstrated that seryl residues could be involved in the formation of «aminoacrylic acid residues, which in turn could combine with lysine to form LAL. Recently, Finley et al (1982) demonstrated that the degree of cysteine oxidation apparently is a key factor in LAL formation.…”

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confidence: 98%

Lysinoalanine in foods

Maga¹

1984

J. Agric. Food Chem.

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The formation of lysinoalanine has been primarily associated with the alkaline treatment or heat processing of proteins. The chemistry, food occurrences, nutritional significance, and methods available for the analysis of this phenomenon, relative to the literature, are discussed.Lysinoalanine (LAL) [JV'-(DL-2-amino-2-carboxyethyl)-L-lysine] represents a unique amino acid that apparently has been present in our food supply for centuries, especially in products that undergo alkaline processing and/or heating of a protein-containing food. In addition, Gross et al. (1975) report that LAL is a natural constituent of cinnamycin and duramycin, which are two peptides present in certain species of Streptomyces.However, it was not until the mid 1960s that LAL was actually identified (Patchornik and Sokolovsky, 1964b;Bohak, 1964). Since that time numerous studies have been reported in an attempt to more completely understand its formation mechanism(s), ways of minimizing its formation, and levels present in foods and, most importantly, to identify its specific nutritional and potential toxicological significance relative to food processing and preparation. Several reviews have appeared that discuss certain aspects of the above (Sternberg and Kim, 1977;de Groot et al., 1977;Struthers, 1981), but no review has attempted to provide an inclusive overview of the entire subject. Thus, the primary objective of this review is to more extensively discuss the literature to date in an effort to summarize our knowledge of LAL in food and to point out areas that need further investigation or clarification.

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“…Alkali treatment of proteins has been shown to cause losses in serine, threonine, cystine, arginine, lysine, and an increase in ornithine (Pickering and Li, 1964; Geschwind and Li, 1964;Zeigler et al, 1967;Mellet, 1968;Blackburn, 1968;DeGroot and Slump, 1969; Parisot and Derminot, 1970;Whiting, 1971;Gottschalk, 1972;Provansal et al, 1975). Amino acid residues in proteins undergo racemization in alkaline solution more readily than do the free amino acids.…”

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confidence: 99%

Reactions of phosphoproteins in alkaline solutions

Sen¹,

Gonzalez-Flores²,

Feeney³

et al. 1977

J. Agric. Food Chem.

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Phosvitin, an egg yolk protein of mol wt 35 500 with 10% phosphate in the form of O-phosphoserine residues (reported value of 119 phosphoserine and one phosphothreonine residues), was used in model systems to investigate the effects of various experimental conditions on the rates of ß elimination of phosphate from the phosphoserine residues and addition of indogenous nucleophiles to the double bond of the dehydroalanines formed. At low concentrations of phosvitin (1-10 X 6 M) the rates were independent of phosvitin concentration but directly dependent on the hydroxide ion concentration of the solution. The activation energies of the ß-elimination and addition reactions were 20.2 and 25.0 kcal/mol, respectively. The rate of the /3-elimination reaction was increased at increased ionic strengths and was markedly increased in the presence of CaCl2. At 1.12 X 10"3 M CaCl2, the rate of ß elimination was 20 times faster than in the absence of CaCl2. The rate of the addition reaction was not significantly affected by CaCl2 or ionic strength.

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The Influence of Alkali Treatment on Native and Denatured Proteins

Cited by 13 publications

References 28 publications

Enzyme-mediated Crosslinking of Wool. Part II: Keratin and Transglutaminase

Enzyme-mediated Crosslinking of Wool. Part II: Keratin and Transglutaminase

Lysinoalanine in foods

Reactions of phosphoproteins in alkaline solutions

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