I have a dataset of proteins that I have blasted against the uniprot-swissprot database.

I'd now like to identify which proteins are likely to have a mitochondrial sub-cellular localisation based on the sub-cellular localisation of their best blast hit in the swiss-prot database. 

The fasta headers of the uniprot proteins look like this:

">sp|Q64602|AADAT_RAT Kynurenine/alpha-aminoadipate aminotransferase, mitochondrial OS=Rattus norvegicus GN=Aadat PE=1 SV=1"
 
I have found a gene ontology mapping file (link below) but the fasta headers don't contain the GO IDs necessary to map them.
ftp://ftp.ebi.ac.uk/pub/databases/GO/goa/external2go/uniprotkb_sl2go

Is there some intermediate file that I need to use and does anyone know where to find it? Any help would be appreciated.
using xslt:

    $ awk -F '|' '/^>/ {printf("%s\n",$2);}' input.fa | while read ACN ; do curl -s "https://www.uniprot.org/uniprot/${ACN}.xml"| xsltproc transform.xsl - ; done
    
    Q64602  Mitochondrion

with transform.xsl:

https://gist.github.com/lindenb/92ae5d03183d1ff56a17684d30dd8f7e

