Thank you so much for your help, I tried reproducing your code with my whole list of proteins and got this warning:
> gene.df<-bitr(genelist, fromType= "SYMBOL", toType=c("ENSEMBL", "ENTREZID"), OrgDb = org.Hs.eg.db)
'select()' returned 1:many mapping between keys and columns
Warning message:
In bitr(genelist, fromType = "SYMBOL", toType = c("ENSEMBL", "ENTREZID"), :
10.71% of input gene IDs are fail to map...
Does that mean there are any incorrect gene symbols in my list?
Do you know how can I filter and remove from my table proteins which are located in one concrete organelle or cell compartment? For example, removing all proteins which are located in cytosol.