Covalent immobilization of organophosphorus hydrolase onto insoluble bovine collagen fibers / Yanhong Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 6 (06/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 6 (06/2014) . - p. 197-206 Titre : Covalent immobilization of organophosphorus hydrolase onto insoluble bovine collagen fibers Type de document : texte imprimé Auteurs : Yanhong Li, Auteur ; Xinju Jia, Auteur ; Biyu Peng, Auteur Année de publication : 2014 Article en page(s) : p. 197-206 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Cinétique chimique Glutaraldéhyde Hydrolase pH Poudre de peaux Température Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : An organophosphorous hydrolase (OPH) was prepared and partially purified from Flavobacterium sp. The crude enzyme, with an activity of 1030U/g, was immobilized onto insoluble bovine collagen fibers (hide powder), instead of collagen membrane, through glutaraldehyde coupling. Optimal conditions of enzyme immobilization and properties of the immobilized enzyme preparation were investigated. Compared to glutaraldehyde tanned and chrome tanned hide powders, non-tanned hide powder showed higher immobilized enzyme activity. The optimal enzyme immobilization conditions are as follows: 10mg of enzyme was immobilized onto 500mg of hide powder in a 50mM phosphate buffer of pH 7.5 at 20°C, and 20% glutaraldehyde offer (based on the hide powder weight) was used to couple the enzyme and collagen fibers. The enzyme activity yield was about 35% and the hide powder immobilized OPH has an enzyme activity of about 7U/g. The immobilized enzyme showed the same temperature and pH profiles as the free enzyme, and it performed at much higher pH and with better thermal stability. The Km value of the immobilized enzyme was a somewhat higher (0.388mM) than that of the free enzyme (0.215mM). The reusability test showed that about 85% activity was retained after 10 use cycles. After storing for eight months at 20°C, the residual activity of the immobilized enzyme preparation was 98%. Note de contenu : - MATERIALS AND METHODS : Materials - Methods (Preparation and partial purification of organophosphorus hydrolase (OPH) from flavobacterium sp. - Preparation of tanned hide powder - OPH activity assay - OPH activity stability against glutaraldehyde - Immobilization of OPH on hide powders - Activity assay and characterization of immobilized OPH) - RESULTS AND DISCUSSION : The influence of glutaraldehyde on OPH activity - Factors affecting immobilization of OPH on hide powder (OPH immobilized on different hide powders - Effect of pH - Effect of glutaraldehyde dosage - Effect and temperature - Effect of added enzyme amount) - Characterization of immobilized OPH (pH and temperature-activity profiles - pH and thermal stability of immobilized enzyme - Kinetics parameters - Operational and storage stability) En ligne : https://drive.google.com/file/d/1-aAAxLzbsyLkcO9tzzpc_gUMX5hFAqhP/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21518 [article]

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Impact of typical surfactants on the collagenolytic and elastinolytic activities of proteases / Yanhong Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 7 (07/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 7 (07/2015) . - p. 227-236 Titre : Impact of typical surfactants on the collagenolytic and elastinolytic activities of proteases Type de document : texte imprimé Auteurs : Yanhong Li, Auteur ; Fenfxiang Luo, Auteur ; Piyu Peng, Auteur ; Bingbing Xu, Auteur Année de publication : 2015 Article en page(s) : p. 227-236 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène Cuirs et peaux -- Analyse Elastine Enzymes protéolytiques Une enzyme protéolytique est une enzyme capable de couper une protéine en plusieurs fragments ou peptides. La trypsine, la papaïne, la pepsine, la chymotrypsine, la plasmine, la subtilisine... sont capables de couper une protéine, chaque enzyme étant spécifique de certains sites particuliers de cette protéine. C'est ainsi, par exemple, qu'une immunoglobuline G est découpée par la papaïne en un fragment Fc et deux fragments Fab, comme l'a montré Porter en 1959. Peptidases Surfactants Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Most proteases exhibit broad-spectrum activities to all of the protein components of skins, thus, the indiscriminate application of proteases will bring out undue and non-selective loss of skin structural proteins, especially collagen and elastin, and lead to loose and damaged grain. Finding the effective ways to control proteases’ activities against collagen and elastin in leather processes is very important. In this work, the influence of typical surfactants on the collagenolytic and elastinolytic activities of frequently used proteases was investigated, and the mechanism was also discussed. The results indicated that the nonionic surfactants had slight effects and anionic surfactants exhibited quite different behaviors on the collagenolytic and elastinolytic activities of selected proteases. Both collagenolytic and elastinolytic activities of trypsin preparations were obviously inhibited by all selected anionic surfactants, especially SDS and SDBS. For the bacteria proteases, their elastinolytic activities were significantly activated and their collagenolytic activities were inhibited to a variable extent by anionic surfactants. Tanners may effectively control the selective action of proteases to collagen and elastin to achieve different requirements through correctly utilizing surfactants. Note de contenu : - MATERIALS AND METHODS : Materials - Methods - Preparation of hide powder-XBR - Preparation of surfactants solutions - Determination of collagenolytic and elastinolytic activities of proteases - RESULTS : Effects of surfactants on elastinolytic activities of proteases - Effects of surfactants on collagenolytic activities of proteases - DISCUSSION : Effects of nonionic surfactants on collagenolytic and elastinolytic activities of proteases - Effects of anionic surfactants on collagenolytic and elastinolytic activities of trypsin - Effects of anionic surfactants on collagenolytic activities of bacteria proteases - Effects of anionic surfactants on elastinolytic activities of bacteria proteases En ligne : https://drive.google.com/file/d/1SGEuhU_mzLwSOMFBXV-VW76c8QZGlyDf/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24376 [article]

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