发信人: hooligan (月是故乡明), 信区: Biology
标 题: Re: Yeast Enolase_2 Help
发信站: Unknown Space - 未名空间 (Mon Mar 29 01:19:10 2004), 站内信件

【 在 macintosh (麦克老狼) 的大作中提到: 】
: 【 在 hooligan (月是故乡明) 的大作中提到: 】
: : In fact, this phenomenon is often observed even for
: : peptide fragmentation. For a 3+ peptide, it is very
: : commonto observe the y(n)2+ and y(n)+ ions at the same
: : time. I bet macintosh can confirm this. :)
: Yes. it is right. When peptides carry more mobile proton, the spectra
: have more doubly charged ions.
: : You experiment sounds interesting, I would like to see
: : the spectra if possible and maybe I can help you to
: : interpret them.
: One question, could you guys get sequence information (> 10 amino acid) by
: low energy CID on protein larger than 15kDa ? I never got it. Maybe I just
: used wrong protein to study ;)

I guess you didn't pick the right protein. :)
My boss did quite a lot of such study before.
For transferrin, a ~75kD glycoprotein, he was able to get
a lot of fragmentation at the C-terminus and got a good
ID using that stretch of sequence.
However, for most other protein, it is really hard to get
enough sequence information for a good protein ID.
ECD, UV laser photodissociation or other high energy
fragmentation methods may producce more fragments.
Low enerygy ways, such as IRMPD, CID and BIRD, are not
going to produce many fragments.

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