发信人: hooligan (月是故乡明), 信区: Biology
标 题: Re: ask a question about mass spectrometry
发信站: Unknown Space - 未名空间 (Mon Jul 12 23:02:00 2004), 站内信件

This approach is good in theory but whether it will work or not
largely depends on your luck and how well all these experiments
are performed.
I guess you have the sequence of this protein and you have some
idea of which try residues may be phosphorylated.
First thing you want to do is to pufify your protein and then
probe your protein with antibody specific to pY on western blot.
If you see it lights up on the western blot, most likely you
have some pY residues in your protein.
Then you proceed with your in-gel digestion and MS analysis.
Do a theorectical digestion of your protein with different
proteases, such as trypsin, Lys-C, Asp-N, and others. Make sure
your pY residues are located in peptides of good size after
the digestion. This increases your chance to see them in MS,
especially for LC-MS.
Good luck!

【 在 comeandgo (春困秋乏夏打盹) 的大作中提到: 】
: I want to study if certain tyrosines on a protein of interest can be
: phosphorylated in vivo, is there any way to use mass spec to address this? how
: about purify the protein by antibody affinity purification and SDS PAGE and
: then cut off the gel piece containing target protein, subject to trypsin
: digestion and then use mass spec to figure out the identity of
: phospho-peptide.


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