Hydration in matrix stabilization of collagen fibres : relevance to mechanistic insight into tanning / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 7 (07/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 7 (07/2003) . - p. 263-272 Titre : Hydration in matrix stabilization of collagen fibres : relevance to mechanistic insight into tanning Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; T. Ramasami, Auteur ; Balachandran Unni Nair, Auteur ; V. Subramanian, Auteur ; Jonnalagadda Raghava Rao, Auteur ; N. N. Fathima, Auteur Année de publication : 2003 Article en page(s) : p. 263-272 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Quantitative understanding of fundamental processes leading to tanning of collagenous tissues has attracted renewed interest in recent times. Although it is traditional to relate formation of crosslinks formed at angstromunit dimensions to increases in the hydrothermal stability of collagenous matrices, further understanding of long range order in collagen supra assembly induced by tanning molecule in nano scale dimensions is becoming more evident. Increases in hydrothermal stability of rat tail tendon fibres induced by precursors of vegetable tannins like catechin, quercetin and gallic acid have now been correlated. Molecular modeling approaches have been employed to simulate and estimate possible net increase in hydrogen bonding energies resulting from binding of collagen with the precursors of vegetable tannins. The stability of collagen fibres against degradation by collagenase has been previously quantitatively related to inhibition of collagenase by tannin molecules. Now an attempt has been made to understand the role of hydration and solvation phenomena in the theory of tanning. A series of thermochemical and NMR investigations have been made with a view to understand at least semi-quantitatively, the role of structure and dynamics of water around collagenous fibres. The binding energies of the complexes of tannin precursors with the collagen-like peptide determined using molecular modeling study has been correlated with the denaturation temperature of tanned collagen and the relaxation times (T1 and T2) of water in tanned fibres. Experimental evidence for the influence of catechin, quercetin and gallic acid on structure and dynamics of free and bound water in collagen fibres has been presented. En ligne : https://drive.google.com/file/d/1Bdj_V5zMF4ugePRNnbyZcUVdRGCkgKnH/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4144 [article]

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Physico-chemical and structural studies on leathers tanned using high exhaust basic chromium sulphate salt / Jonnalagadda Raghava Rao in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIII, N° 5 (07/1998)

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIII, N° 5 (07/1998) . - p. 139-147 Titre : Physico-chemical and structural studies on leathers tanned using high exhaust basic chromium sulphate salt Type de document : texte imprimé Auteurs : Jonnalagadda Raghava Rao, Auteur ; T. Ramasami, Auteur ; Balachandran Unni Nair, Auteur ; V. Subramanian, Auteur ; B. Chandrasekaran, Auteur Année de publication : 1998 Article en page(s) : p. 139-147 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : One of the approaches towards minimizing the chrome pollution is to increase the uptake of chromium during tanning through the application of high exhaust basic chromium sulphate slats. A high exhaust chrome tanning salt exhibiting chrome uptake levels of above 82% during tanning has been prepared in our laboratory. The present investigation deals with the influence of high exhaust chrome tanning salt on the hysical, chemical and structural properties of the final leather. The study shows that there is an increasef fixation of chromium to the collagen matrix which in turn influences the uptake of retanning agents, dyes and fatliquors during post tanning operation. This investigation also indicates a realistic saving of 20-25% inpost tanning chemicals when the leathers are tanned with high exhaust BCS salt. Note de contenu : - Tanning trials with commercial BCS salt - Tanning trials with high exhaust BCS salt - Optimization of post-tanning needs of leathers tanned with high exhaust BCS salt - Chemical analysis - Scanning electron microscopy - Physical testing Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4518 [article]

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Role of phenolics in the stabilization of collagen / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 4 (04/2004)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIX, N° 4 (04/2004) . - p. 157-163 Titre : Role of phenolics in the stabilization of collagen Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; T. Ramasami, Auteur ; V. Subramanian, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2004 Article en page(s) : p. 157-163 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Stabilization of the fibrous protein collagen is important in biological and industrial processes. In the present study, three representative phenolic compounds - catechol, resorcinol and pyrogallol have been selected to probe their role in the stabilization of collagen. Hydrothermal stability and the stability against enzyme (collagenase) have been considered as the measures for the stabilization process. It has been found that catechol increased the hydrothermal stability of the collagen fibres by 6.5 °C and also the catechol treated collagen fibres exhibited higher resistance against the degradation by enzyme collagenase. Resorcinol treated collagen fibres exhibited least resistance both against heat and collagenase. Pyrogallol increased the shrinkage temperature of the collagen fibres by 4.5 °C and resisted the activity of collagenase to a considerable extent. Molecular modeling studies have provided clear evidence for the significance of electrostatic and hydrogen bonded interaction in the stabilization of collagen by phenolic compounds. En ligne : https://drive.google.com/file/d/1I7oW6yeliem0gIk3ZWh0q9dOZZYYYwuw/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4189 [article]

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A semi-empirical quantum mechanical modeling study on the interaction of collagen-like peptides with polyphenolic molecules : An attempt to gain insights into vegetable tanning / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 7 (07/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 7 (07/2003) . - p. 273-278 Titre : A semi-empirical quantum mechanical modeling study on the interaction of collagen-like peptides with polyphenolic molecules : An attempt to gain insights into vegetable tanning Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; V. Subramanian, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur ; T. Ramasami, Auteur Année de publication : 2003 Article en page(s) : p. 273-278 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A semi-empirical quantum mechanical PM3 hamiltonian based molecular modeling has been used to study the interactions of collagen-like peptide with polyphenolics. A collagen-like peptide 9-mer sequence has been built and interacted with the polyphenolic molecules. Most of the complexes of the peptide sequence and polyphenolic molecule exhibited hydrogen bonding. The binding energies of the complexes were in the range of 6.5 - 20 kcal/mol. Complexes of gallic acid exhibited the least binding energies. Epicatechin complexes exhibited higher binding energies with the collagen-like peptide sequence. En ligne : https://drive.google.com/file/d/1NKAhmRIfS0pZFdyQWs5Cphz-oIlJQsoI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4145 [article]

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