At 12:17 PM -0500 2/21/01, Wei Wu wrote:
Wei-
Note that Swiss Prot lists conflicts in the sequence of BSA
that will affect MW. Kathy Schegg here once sequenced a fragment of
reduced, carboxymethylated BSA from a digest to test the Procise and
protocol. As luck would have it, the fragment she sequenced was one
of the ones containing a "conflict", and the Edman sequence agreed
with the reported conflict, NOT with the SWISS-PROT sequence.
For additional details contact her at schegg@med.unr.edu. It
is surprising that they don't correct the original sequence!
David
>Hi Jim,
>
>We've had trouble getting the theoretical mass of BSA. From a
>thermobioanalysis application note, it's 66431 Da. However, if we go
>directly from the sequence in Swiss Prot, the mass is 66433 Da for the
>reduced form, and 66398 for the form with disulfides (17 of those). I guess
>we are dealing w/ the form with disulfides. Yet, if the accuaracy is 0.1%
>like Arnie said, it'd be hard to differentiate the two. We also found that
>if we used the BSA and RNase A to calibrate the double charge peak of BSA,
>it was off from calculated by either of the numbers above, which probably
>means the BSA we used has a different mass, as we are pretty confident about
>RNase A.
>
>Regards,
>Wei
>
-- David A. Schooley Dept. of Biochemistry/330 Univ. of Nevada Reno, NV 89557 schooley@unr.edu tel: (775) 784-4136; fax (775) 784-1419 NOTE NEW AREA CODE: Mandatory after 5/15/99
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