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1.
A novel metalloprotease from Bacillus cereus for protein fibre processing
Fernanda de Sousa, Suzana Jus, Anita Erbel, Vanja Kokol, Artur Cavaco-Paulo, Georg M. Gübitz, 2007, original scientific article

Abstract: A novel protease produced by Bacillus cereus grown on wool as carbon and nitrogen source was purified. B. cereus protease is a neutral metalloprotease with a molecular mass of 45.6 kDa. The optimum activity was at 45 °C and pH 7.0. The substrate specificity was assessed using oxidized insulin B-chain and synthetic peptide substrates. The cleavage of the insulin B-chain was determined to be Asn3, Leu6, His10-Leu11, Ala14, Glu21, after 12 h incubation. Among the peptide substrates, the enzyme did not exhibit activity towards ester substrates; with p-nitroanilide, the kinetic data indicate that aliphatic and aromatic amino acids were the preferred residues at the P1 position. For furylacryloyl peptides substrates, which are typical substrates for thermolysin, the enzyme exhibited high hydrolytic activity with a Km values of 0.858 and 2.363 mM for N-(3-[2-Furyl]acryloyl)-Ala-Phe amide and N-(3-[2-Furyl]acryloyl)-Gly-Leu amide, respectively. The purified protease hydrolysed proteins substrates such as azocasein, azocoll, keratin azure and wool.
Keywords: textile finishing, enzymatic modification, wool fibre, enzymes, Bacilus cereus, specificity, kinetics, metalloprotease
Published: 01.06.2012; Views: 1026; Downloads: 67
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2.
The influence of enzymatic treatment on wool fibre properties using PEG-modified proteases
Suzana Jus, Marc Schroeder, Georg M. Gübitz, Elisabeth Heine, Vanja Kokol, 2007, original scientific article

Abstract: The main contribution of the presented work was to introduce the use of proteases modified with the soluble polymer polyethylene glycol (PEG) in the bio-finishing process of wool fibres, to target enzyme action to the outerparts of wool fibres, i.e. to avoid the diffusion and consequent destroying of the inner parts of the wool fibre structure, in the case of native proteases using. Different proteolytic enzymes from Bacillus lentus and Bacillus subtilis in native and PEG-modified forms were investigated and their influence on the modification of wool fibres morphology surface, chemical structure, as well as the hydrolysis of wool proteins, the physico-mechanical properties, and the sorption properties of 1:2 metal complex dye during dyeing were studied. SEM images of wool fibres confirmed smoother and cleaner fibre surfaces without fibre damages using PEG-modified proteases. Modified enzyme products have a benefit effect on the wool fibres felting behaviours (14%) in the case when PEG-modified B. lentus is used, without markedly fibre damage expressed by tensile strength and weight loss ofthe fibre. Meanwhile the dye exhaustion showed slower but comparable level of dye uptake at the end of the dyeing.
Keywords: volnena vlakna, proteolitski encimi, encimske modifikacije, sorpcija barve, morfologija vlaken, wool fibres, proteolytic enzymes, enzyme modification, felting, dye sorption, protein hydrolysis, XPS-analysis, fibre morphology
Published: 01.06.2012; Views: 1666; Downloads: 65
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