N-15 source??

J. Casey Lippmeier jcasey at wizard.net
Sun Jul 26 10:08:55 EST 1998

I'm assuming that you want to grow up an organism that express a protein
you are interested in doing NMR structural studies on.  Chances are that
unless you are dealing with an organism that can fix nitrogen from
exclusively inorganic sources (such as ammonium chloride or sulfate) your
will have problems in either a. labeling your protien effectively (as
unlabled organic nitrogen sources (amino and nucleic acids in your growth
media) will preferentially be used in protein biosyntheis), or b. you will
have trouble growing your cells in media containing inorganic nitrogen as
the exclusive nitrogen source.  I expect that what you are really after is
a growth media for your cells in which all the organic nitrogen is N-15.
As stated below, Martek provides such media at competitive prices.  They
also sell unlabled test versions of their medias for optimizing your
growth parameters and purification techniques.

-J. Casey Lippmeier

On Thu, 23 Jul 1998, Chen Ho An wrote:

> Carsten Hohoff (hohoff at uni-muenster.de) wrote:
> : What is the best (cheapest) source for N-15 (ammonium chloride 
> : or sulfate) ??
> Don't know about best (I think they are probably all the same), but what
> little I know of is that Martek is very competitive in its pricing.  But
> I would suggest that you look at all the companies involved (CKgas,
> Goss and there might be others) and prices might be different in
> different countries.   Compare and, ahem, haggle a bit?

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