Egta

u can use mercuric chloride(hgcl2), edta, egta etc :D

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there apparently isn't only one relax buffer as one link says: 10 mM EGTA, 25 μM CaCl2, 20 mM MOPS, 50 mM KCl, 6.8 mM MgCl2, 12 mM phosphocreatine, 5 mM Na2ATP, ... http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WK6-4KGPPSC-2&_user=10&_coverDate=09%2F30%2F2006&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1202251623&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=998bba3e664e992230f6450a7eb1fe3b ...

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