Expression of a cGMP compatible Lucilia sericata insect serine proteinase debridement enzyme.

Previously, we demonstrated the effectiveness of a research grade recombinant chymotrypsin, derived from the larvae of Lucilia sericata, in "debriding" slough/eschar from venous leg ulcers ex vivo. Furthermore, we were able to formulate this enzyme for successful delivery to in vitro wound healing assays, from a prototype hydrogel wound dressing, and showed that enzyme delivered in this way could degrade wound tissue ex vivo. Recently, to progress biotechnological development of the enzyme as a potential therapeutic product, we explored expression using current good manufacturing practice (cGMP) guidelines, and now report that a recombinant chymotrypsin I zymogen from L. sericata can be expressed in the cGMP acceptable strain of Escherichia coli (BLR-DE3). In addition, the conditions required for purification, refolding and activation of the chymotrypsinogen have been determined. The activated enzyme was stable, and effective in digesting wound slough/eschar tissue. To summarise, we have successfully initiated the production and characterisation of a novel cGMP compatible product for use in future clinical trials.