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The non-collagenous proteins of skin - Their characterisation and significance in leather processing / G. A. Balian in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 54, N° 5 (05/1970)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 54, N° 5 (05/1970) . - p. 171-182 Titre : The non-collagenous proteins of skin - Their characterisation and significance in leather processing Type de document : texte imprimé Auteurs : G. A. Balian, Auteur ; J. H. Bowes, Auteur Année de publication : 1970 Article en page(s) : p. 171-182 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acides aminés Les acides aminés (ou aminoacides) sont une classe de composés chimiques possédant deux groupes fonctionnels : à la fois un groupe carboxyle –COOH et un groupe amine –NH2. Parmi ceux-ci, les acides α-aminés se définissent par le fait que leur groupe amine est lié à l'atome de carbone adjacent au groupe acide carboxylique (le carbone α), ce qui leur confère la structure générique H2N–CHR–COOH, où R représente la chaîne latérale, qui identifie l'acide α-aminé. Les acides α-aminés jouent un rôle fondamental en biochimie comme constituants élémentaires des protéines : ils polymérisent en formant des liaisons peptidiques qui aboutissent à de longues chaînes macromoléculaires appelées peptides. Caractérisation Cuirs et peaux de veaux Extraction (chimie) Protéines Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The composition of the skin and the variations in the relative amounts of collagen and non-collagenous proteins in the skin with the type of animal, age and nutritional level are considered. The non-collagenous protein shave been divided into four fractions on the basis of solubility and ease of extraction from skin. About 30% of the non-collagenous protein is extracted by phosphate buffer at pH 9.0 and by neutral salt solutions, a further "àù by dilute alkali, pH 12.5, and the remaining 30% or so remains in association with the insoluble collagen. Ten to twenty per cent non-collagenous protein dissolves in acetic acid together with acid-soluble collagen. The non-collagenous protein extracted by phosphate buffer, dilute alkali and acetic acid have been analysed for amino acid composition and examined by ion exchange and molecular sieve chromatography and acrylamide gel electrophoresis. The protein extracted by phosphate buffer has been shown to consist primarily of plasma proteins and is considered to arise from the blood supply and no have no function specific to skin. The non-collagenous proteins extracted by acid and alkali differ in amino acid composition. Each canbe separated into a major and several minor components by acrylamide gel electrophoresis but few, if any, of these appear to be common to both extracts. The major component of the alkaline extract if of high molecular weight and is closely associated with the collagen. It represents a high proportion of the total non-collagenous protein of skin. The acid-soluble fraction is also closely associated with the collagen ; it contains an excess of acidic residues and is probably bound to the collagen by electrostatic forces. The results as a whole demonstrate that thematrix of skin consists of a complex system of non-fibrous proteins, some of which are difficult to remove from association with collagen and vice versa. Their possible function in the stabiilisation of skin structure is examined. These findings and recent advances in our knowledge of the structure and properties of collagen are discussed in relation to leather processing. Note de contenu : - Composition of skin - Characterisation of the non-collegenous protein : Extraction - Alkaline extract - Acetic acid extracts - Insoluble protein - Function of the non-collagenous proteins - Implications in leather processing - Table 1 : Protein extracted from calf skin - Percentage of total skin protein - Table 2 : Amino acid composition of non-collagenous protein fractions extracted from calf skin En ligne : https://drive.google.com/file/d/1hIXcYHobRfD93QNnMdzYjNzz-3nDaEIN/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37002 [article]

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Waterproofing of sole leather / P. L. Muthiah in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 54, N° 5 (05/1970)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 54, N° 5 (05/1970) . - p. 183-201 Titre : Waterproofing of sole leather Type de document : texte imprimé Auteurs : P. L. Muthiah, Auteur ; V. Mohanaradhakrishnan, Auteur Année de publication : 1970 Article en page(s) : p. 183-201 Langues : Anglais (eng) Catégories : Alun Couleur Cuir Décapage Essais (technologie) Humidité -- Absorption:Eau -- Absorption Imperméabilisation Produits de nourriture du cuir Retannage Semelle Traitement chimique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The continued and increasing competition from synthetic materials in ail branches of leather industry emphasises the importance of investigations concerned with the improvement of water resistance of leather. Literature survey indicates that a wide variety of materials and methods have been used for improving the water resistance of leather. A suitable material for this purpose demands the following qualities : (a) with a minimum quantity of the material considerable increase in water resistance ; (b) uniform effect throughout the thick-ness of the leather, otherwise the effect will be lost in short time ; (c) preservation of the air and water vapour permeability ; (d) retention of the qualities such as : grip, flexibility and colour ; (e) non-attainment of thermoplastic properties, i.e. the leather must be soft and flexible in a cold climate and should not be sticky at high temperature ; (f) the method of application must be simple ; (g) the materials must be easily available in the market in large quantities and must be cheap. In order to find a suitable waterproofing material for vegetable tanned sole leather, a preliminary study was undertaken using various waterproofing materials and methods, viz. impregnation with different materials, retanning with zirconium, chromium and aluminium salts and basic aluminium sulphate treatment. Preparation of crust vegetable sole leather and the sampling method were the same as described earlier. The well known Kubelka's apparatus was used for determining the water absorption of leathers. Note de contenu : - Impregnation with different materials - Retanning with zirconium, chromium and aluminium salts : Studies using basic aluminium sulphate - Studies on the improvements - Neutralisation of colour - Chemical treatments - Field tests - Results and discussion : Effect of impregnation - Retanning - Studies using basic aluminium sulphate - Effect of oiling before alum treatment - Effect of oiling after alum treatment - Mechanism of waterproofing - Studies on the improvement of colour - Field tests - Table 1 : Effect of waterproofing with various materials - Table 2 : Effect of retanning and alum dipping - Table 3 : Effect of stripping - Table 4 : Effect of re-use of alum liquor - Table 5 : Effect of oiling - Table 6 : Colour of the leathers, processed by various methods - Table 7 : Water absorption of leathers after different treatments En ligne : https://drive.google.com/file/d/1j4LfXSuut-MMCX_O2ejEjIaa-jVTxilK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37008 [article]

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