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Cleaning protocols for crystallization robots: preventing protease contamination
Author(s) -
Naschberger Andreas,
Fürnrohr Barbara G.,
DunzendorferMatt Theresia,
Bonagura Christopher A.,
Wright David,
Scheffzek Klaus,
Rupp Bernhard
Publication year - 2015
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x14026053
Subject(s) - protease , crystallization , chemistry , contamination , metalloproteinase , degradation (telecommunications) , chromatography , enzyme , biochemistry , computer science , biology , organic chemistry , ecology , telecommunications
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 m M . 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.