Go Back   Molecular Biology Forum > Molecular Research Topics Forum > Proteomics Forum > Mass Spectrometry Forum
Register Blogs FAQ Members List Calendar Science Groups New! Arcade Search Today's Posts Mark Forums Read

Mass Spectrometry Forum Discuss and post questions about LC-MS, Q-STAR, MALDI-TOF, and other Mass Spectrometry Questions in the Mass Spec Forum.


peptide mass fingerprint query

Mass Spectrometry Forum

Discuss and post questions about LC-MS, Q-STAR, MALDI-TOF, and other Mass Spectrometry Questions in the Mass Spec Forum.



Register Molecular Biology Forums
Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 10-12-2007, 12:53 PM
Pipette Filler
Points: 371, Level: 7Points: 371, Level: 7Points: 371, Level: 7
Activity: 0%Activity: 0%Activity: 0%
 

Join Date: Oct 2007
Posts: 2
mass spec novice RSS Feed
Default peptide mass fingerprint query

Can anyone explain what exactly the following mass spec result means - i have an unknown protein that was subject to MALDI TOF MS and the result from mascot was this 'PREDICTED:Similar to X', i am not sure what exactly this means - does it mean that my protein is similar to a predicted protein X sequence in the database? Is there the possibility that my protein is protein X but that cannot be confirmed? or does it mean that my protein is definitely not protein X but something very similar?

thanks in advance
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!Spurl this Post!Reddit!
Reply With Quote
Alt Today
Advertising
Google Adsense
 
This advertising will not be shown
in this way to registered members.
Register your free account today
and become a member on
Molecular Biology Forum
Standard Sponsored Links

  #2 (permalink)  
Old 10-12-2007, 02:52 PM
danfive's Avatar
Nobel Laureate
Points: 2,293, Level: 30Points: 2,293, Level: 30Points: 2,293, Level: 30
Activity: 100%Activity: 100%Activity: 100%
 

Join Date: Jul 2007
Location: Houston TX
Posts: 507
danfive RSS Feed
Default Re: peptide mass fingerprint query

All of the possibilities you mention are plausible. Including more info on source of protein, modification, digestion, and P-values of database search hit are routine when describing spec results. Good luck!
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!Spurl this Post!Reddit!
Reply With Quote
  #3 (permalink)  
Old 10-13-2007, 10:04 AM
Pipette Filler
Points: 371, Level: 7Points: 371, Level: 7Points: 371, Level: 7
Activity: 0%Activity: 0%Activity: 0%
 

Join Date: Oct 2007
Posts: 2
mass spec novice RSS Feed
Default Re: peptide mass fingerprint query

Hi thanks for your reply, i know a bit about MS as i've done it before but i have never got this 'predicted:similar to' before that's why i'm confused - the protein match is from the same species, same molecular weight, same isoelectric point and a good ststistically significant mowse score - so, does 'predicted' mean that the protein it is matching to is actually not in the database but its predicted sequence (from cDNA) is there, and, my protein is similar to that? my protein might be that protein?

sorry for going on! really need to understand this! thanks again
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!Spurl this Post!Reddit!
Reply With Quote
  #4 (permalink)  
Old 10-13-2007, 05:19 PM
danfive's Avatar
Nobel Laureate
Points: 2,293, Level: 30Points: 2,293, Level: 30Points: 2,293, Level: 30
Activity: 100%Activity: 100%Activity: 100%
 

Join Date: Jul 2007
Location: Houston TX
Posts: 507
danfive RSS Feed
Default Re: peptide mass fingerprint query

Quote:
Originally Posted by mass spec novice View Post
... the protein match is from the same species, same molecular weight, same isoelectric point and a good ststistically significant mowse score -
All of these things point to you isolating the right protein, do you have various (3-5) m/z values that are selected as matched peptides for the same protein ID; i.e., various peptide matches for that protein. You can also do an antibody-based assay like ELISA or Western to back up your protein isolation. And as always, if all else fails you can REPEAT, REPEAT, REPEAT the experiment.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!Spurl this Post!Reddit!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
96 well plate peptide synthesis service glbiochem Chit Chat 0 11-15-2007 04:22 AM
disulfide cleavage dpar Peptide Forum 3 01-26-2007 12:16 AM


All times are GMT. The time now is 08:15 PM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
Copyright 2005-2007 Molecular Station | All Rights Reserved