30 research outputs found
Specificities of a chemically modified laccase from trametes hirsuta on soluble and cellulose-bound substrates
Laccases could prevent fabrics and
garments from re-deposition of dyes during
washing and finishing processes by degrading the solubilized dye. However, laccase action must be restricted to solubilized dye molecules thereby
avoiding decolorization of fabrics. Chemical
modification of enzymes can provide a powerful tool to change the adsorption behaviour of enzymes on water insoluble polymers. Polyethylene glycol (PEG) was covalently attached onto a laccase from Trametes hirsuta. Different molecular
weights of the synthetic polymer were tested
in terms of adsorption behaviour and retained
laccase activity. Covalent attachment of PEG
onto the laccase resulted in enhanced enzyme
stability while with increasing molecular weight of attached PEG the substrate affinity for the laccase conjugate decreased. The activity of the modified laccases on fibre bound dye was drastically reduced decreasing the adsorption of the enzyme on various fabrics. Compared to the 5 kDa PEG laccase conjugate (K/S value 47.60
Restricting detergent protease action to surface of protein fibres by chemical modification
Due to their excellent properties, such as
thermostability, activity over a broad range of pH and
efficient stain removal, proteases from Bacillus sp. are
commonly used in the textile industry including industrial
processes and laundry and represent one of the most
important groups of enzymes. However, due to the action
of proteases, severe damage on natural protein fibres such
as silk and wool result after washing with detergents
containing proteases. To include the benefits of proteases in
a wool fibre friendly detergent formulation, the soluble
polymer polyethylene glycol (PEG) was covalently
attached to a protease from Bacillus licheniformis. In
contrast to activation of PEG with cyanuric chloride (50%)
activation with 1,1′-carbonyldiimidazole (CDI) lead to
activity recovery above 90%. With these modified
enzymes, hydrolytic attack on wool fibres could be
successfully prevented up to 95% compared to the native
enzymes. Colour difference (ΔE) measured in the three dimensional colour space showed good stain removal
properties for the modified enzymes. Furthermore, half-life
of the modified enzymes in buffers and commercial
detergents solutions was nearly twice as high as those of
the non-modified enzymes with values of up to 63 min. Out
of the different modified proteases especially the B.
licheniformis protease with the 2.0-kDa polymer attached
both retained stain removal properties and did not
hydrolyse/damage wool fibres
Site-selective protein-modification chemistry for basic biology and drug development.
Nature has produced intricate machinery to covalently diversify the structure of proteins after their synthesis in the ribosome. In an attempt to mimic nature, chemists have developed a large set of reactions that enable post-expression modification of proteins at pre-determined sites. These reactions are now used to selectively install particular modifications on proteins for many biological and therapeutic applications. For example, they provide an opportunity to install post-translational modifications on proteins to determine their exact biological roles. Labelling of proteins in live cells with fluorescent dyes allows protein uptake and intracellular trafficking to be tracked and also enables physiological parameters to be measured optically. Through the conjugation of potent cytotoxicants to antibodies, novel anti-cancer drugs with improved efficacy and reduced side effects may be obtained. In this Perspective, we highlight the most exciting current and future applications of chemical site-selective protein modification and consider which hurdles still need to be overcome for more widespread use.We thank FCT Portugal (FCT Investigator to G.J.L.B.), the EU (Marie-Curie CIG to G.J.L.B. and Marie-Curie IEF to O.B.) and the EPSRC for funding. G.J.L.B. is a Royal Society University Research Fellow.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nchem.239