Surface Modification of Cellulose Acetate with Cutinase and ...
Surface Modification of Cellulose Acetate with Cutinase and ...
Surface Modification of Cellulose Acetate with Cutinase and ...
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1. Introduction<br />
Enzymatic Hydolysis <strong>of</strong> Wool <strong>with</strong> a Genetically Modified Subtilisin E<br />
The morphology <strong>of</strong> wool is highly complex, not only in the fibre stem but also on the<br />
surface as well. It is in fact the surface morphology that plays an important role in the<br />
wool processing. Unwanted effects such as shrinkage, felting <strong>and</strong> barrier <strong>of</strong> diffusion<br />
are most probably due to the presence <strong>of</strong> wool scales on the fibre surface (Negri et al.,<br />
1993).<br />
Wool surface treatment <strong>with</strong> proteolytic enzymes seems to be a promissing alternative<br />
to the traditional pollutant Chlorine/Hercosett process. However, enzymatic reaction<br />
needs to be controlled, either by chemical or genetic modification, to avoid diffusion <strong>of</strong><br />
enzyme into wool cortex <strong>and</strong> consequent fibre damage (Silva et al., 2004; Silva et al.,<br />
2005).<br />
In contrast to chemical modification, the size <strong>and</strong> entire sequence <strong>of</strong> aminoacids <strong>of</strong> a<br />
recombinant high molecular weight protein can be precisely controlled bythe DNA<br />
coding sequence. In previous work developed by our group different cloning strategies<br />
were used to increase subtilisin E molecular weight. Although the recombinant enzymes<br />
were expressed, the soluble <strong>and</strong> active form <strong>of</strong> proteins was not achieved (Araújo et al.,<br />
2008).<br />
In this work we have used a protein based polymer to solubilize subtilisin E. A protein<br />
polymer is a polypeptide chain composed <strong>of</strong> amino acids sequences, commonly found<br />
in nature, which are arranged <strong>with</strong>in a block or a set <strong>of</strong> blocks which are repeated in<br />
t<strong>and</strong>em, producing a high molecular weight repetitive protein (Urry, 2006). This type <strong>of</strong><br />
polymers has been used for the solubilization <strong>and</strong> purification <strong>of</strong> hard proteins (Banki et<br />
al., 2005, Trabbic-Carlson et al., 2004). Since this is a high molecular weight polymer<br />
this may also function as an interesting possibility to functionalize subtilisin E for wool<br />
finishing applications.<br />
The present work compares the behaviour <strong>of</strong> two proteases, the commercial subtilisin,<br />
Esperase, <strong>with</strong> low molecular weight, <strong>and</strong> a chimeric hight molecular weight subtilisin-<br />
GAG220, in the diffusion <strong>and</strong> hydrolytic attack to wool fibres.<br />
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