Subject: What do EDTA and EGTA do, what are their differences, and their uses.

I've been trying to find out what the differences between EDTA and EGTA are.  I 
know that EDTA is an ion chelator and often used to sequester ions in a solution 
to stop enzyme activity, but what ions does it chelate?  There are some 
applications that call for EGTA, which also chelates ions.  Why the difference 
in applications?  Web searches keep sending me to sites about EDTA therapy 
without telling me much information about LABORATORY applications, and I can 
find very little information on EGTA.  I'm curious to know why either one of 
these chemicals are used.

Re: What do EDTA and EGTA do, what are their differences, and their uses.