Re: Chromatography and methionine

Deb McMillen (mcmillen@morel.uoregon.edu)
Fri, 20 Nov 1998 12:04:19 -0800 (PST)

Vernon, I can't give you an HPLC method for that resolution--you may want
to do amino acid analysis to determine this. However, there is a paper by
Jakubowski and Goldman (Microbiol. Rev. 56, 412-429 1992) that addresses
this problem. In Table I they give the relative rates in E. coli of
activation of norleucine by methionyl-tRNA synthetase. (I have to thank
Chris Halkides for pointing out this reference to me.)

Deb McMillen
Institute of MOlecular Biology
University of Oregon
EUgene OR 97403

On 20 Nov 1998, VERNON SHOUP wrote:

>
> We are working with an E.coli-produced recombinant protein (21,000 MW, 3 methionines, no cysteines) that apparently has some methionine-to-norleucine variants. One of these variants chromatographs very closely to the parent protein across a number of purification techniques: cation and anion exchange, HIC, acid rpHPLC. Does anyone have any suggestions about how to specifically enhance resolution between these species, so we can quantitate the variant without doing a peptide map?
>
> Vernon
>
> Vernon A. Shoup
> Regeneron Pharmaceuticals, Inc.
> Rensselaer, NY 12144
>
> (518)488-6012
> vernon.shoup@regpha.com
>