Hi,

I assume you're trying to read a sequence from a fragmentation spectrum?

You could consider sharing the spectrum and letting the community help you deduce the sequence.

Hello Shubham,

for protein sequencing upon MS/MS you will need to understand peptide fragmentation rules.

Have a look to this tutorial for de novo peptide sequencing:

http://www.ionsource.com/tutorial/DeNovo/DeNovoTOC.htm

Therein contained rules apply for any MS/MS analysis/experiment; you will also find very usefull references and additional reading at the end.

For advanced studies you may have a look to:

Article Fragmentation Pathways of Protonated Peptides

Hope it helps.