Cleaning protocols for crystallization robots: preventing protease contamination

The protease in the commonly used commercial low-foam enzyme cleaner Zymit cannot be completely blocked by EDTA, a widely used inhibitor of metalloproteases, at concentrations of up to 5 mM. Severe protein degradation was observed in crystallization drops after EDTA-containing wash steps unless residual Zymit protease was removed with NaOH at a concentration of at least 0.1 M. Wash steps with 0.1% SDS were also ineffective in completely removing the remaining Zymit activity. Protocols including wash steps with at least 0.1 M NaOH, as for example specified in the original ZENM protocol, are recommended to completely deactivate Zymit protease activity.

Source: Acta Crystallographica Section F - December 24, 2014 Category: Biochemistry Authors: Naschberger, A.Fürnrohr, B.G.Dunzendorfer-Matt, T.Bonagura, C.A.Wright, D.Scheffzek, K.Rupp, B. Tags: crystallization robotics protease protease inhibitor Zymit cleaning protocol research communications Source Type: research