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How To Do Pathway Mapping Using Kegg/Kaas?

More specifically, after I get the KO numbers for each gene, how do I make the actual assignment of each gene to a specific pathway? I suppose I will have to download a database and parse it somehow, but since there are quite a few of them I'm a bit confused!

Do you have any other method to suggest (except KEGG)?

kegg pathway

You know that you can also download species-specific pathways?

No, I didn't know that! Nevertheless, I want to find pathways in a metagenome that doesn't exist in KEGG so I have to do it from the beginning.

2 answers

You can do this mapping using custom scripts by downloading the flat file of KO list here. You can use that list to get pathway associated with each KO numbers. If you want the pathway mapping you can check the mapping file here.

If you want to perform enrichment analysis, you may take a look at SubPathwayMiner

I downloaded the two files but there are some KO numbers that don't exist in the KO list file... Is this possible?

I used KAAS to get the KO numbers (using the predefined prokaryotic template). Should I use some other program/service to get the KO numbers?

AFAIK, these two are the most recent data from KEGG. I am not sure about the reason behind missing KO number. I would recommend you to check with KEGG curators regarding this.

Just for your info... I asked the KEGG curators as you told me Khader and they told me that this is normal; the "ko.list" file contains only KOs that are assigned to a certain pathway. Hence, if a KO doesn't appear in "ko.list" then this is because it wasn't possible for it to be assigned to a pathway (poor characterization).

Thanks for the feedback Panos. This will be useful for the future reference.

You should check the KEGG API through SOAP, also because the access to the KEGG ftp is now restricted without a licence.

This API contains various commands that may help you in mapping a KO ID to a pathway, like the command "get_pathways_by_kos"

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