whence Coomassie?

mills_j at mscf.med.upenn.edu mills_j at mscf.med.upenn.edu
Sun Oct 4 22:41:28 EST 1992


BI1RGW at ibm.shef.ac.uk writes:
> Hello Netland.
> 
> Can anyone remind me of the details of what, how and when Coomassie R/G bind
> to proteins?  As I recall, R binds slower but is more sensitive - but what do
> they bind?  I have at the back of my mind some vague inkling about lysine
> residues - but what about arginine, and what about the N-terminus?
> 
> I'm sure this is a FAQ, but...all comments, recollections, anecdotes welcome.

    You know, I spent a little bit of time researching just what exactly Coo-
massie dye binds to.  The basic conclusion that I reached at the time was 
that either nobody knows, or I was looking in the wrong places.  There is a
whole chapter on various anionic dyes in a 1985 book on electrophoresis, but
as I remember it, other than a lot of interesting stuff about the history and
some explanations of sensitivity and a good bit of detail about linearity of
staining intensity to mass of protein, there wasn't much about binding.  All
I remember was that Coomassie was supposed to bind free amino groups.  Of
course, that would dictate lysine binding, but I got the impression the in-
teraction between dye and protein wasn't that specific.

    I'd be a little surprised if this were a FAQ, but if it is, or if there 
are any dye organic chemists out there chomping at the bit to enlighten this
cell biologist who's out of his league, I'd be interested.
-- 
                                  JCM                      
             |---------------------------------------------|
             |--Mills_J at a1.mscf.upenn.edu (Jason Mills)----|
             |"Why would anyone want both an MD and a PhD?"|
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