Jim Bloom wrote:
> Regarding our missing His and Lys problems. Thanks to Tim regarding the
> missing His in the first cycle, his response was posted to the bulletin board.
> The missing lysines stumped everyone except Mark Aldridge at Agilent. It seems
> if you are using the Peptide method and have "old" S2/3 and/or S3 and have a
> lysine less than 10 residues in...you will see it. If your lysine is more than
> 10 residues in, you will not see it as recovery of lysines is greatly
> compromised by the "old" reagents. We replaced S3 with fresh stuff and lo and
> behold all the "missing" lysines made an appearance!! The first of five
> lysines in our problem peptide is located at residue 15... Mark's
> recommendation is that S2/3 and S3 should be discarded after 90 days from
> receipt.
>
> Weather inconsequential: I would like to suggest venues for the EB's proposed
> two new workshops. Berkeley is due east of the Golden Gate and is thus
> directly exposed to Pacific ocean winds. The Berkeley marina has a nice park
> that would be perfect for the 1/2 day kiteflying workshop. The Cal campus with
> its towering redwoods would be appropriate for the 3 1/2 day kite retrieval
> workshop. Now really, Omaha!!??
>
> Jim
>
Regarding the low yield of lysines, I would like to add that peroxides formed
in aged solvents can be the cause of some problems. The reference below addressed
such a problem by building a system to inject argon into solvent A bottle of a ABI
477A sequencer in a controlled way during the runs. The durability of the solvent
increased very much.
Fontes, W., Cunha, R.B., Sousa, M.V. and Morhy, L.M. (1998). Improving the
recovery of lysine in automated protein sequencing. Analytical Biochemistry 258,
259-267.
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Prof. Marcelo Valle de Sousa, Director
Brazilian Center for Protein Research and Services
Laboratory of Protein Chemistry and Biochemistry
Departament of Cell Biology
University of Brasilia
Brasilia - DF Brazil
CEP 70910-900
Tel: (61)307-2142
Fax: (61)272-4548
e-mail: mvsousa@unb.br
http://www.lbqp.unb.br/cbsp/
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