Finding an antibody for a weird species ! - What matters in protein blast? identity or positive? (Oct/30/2008 )

I'm gonna purchase an antibody raised against a human native protein and use it for detecting the insect protein on the western ... When I blast the the protein sequence of the insect against the human sequence, it turns out that there is 88% identity and 92% positive? which one should matter to me?

None

Unfortunately, antibodies works by recognizing epitopes of their target. So 88% of homology does not indicate that the epitope recognized by the ab will be conserved in the insect protein.

I suggest you check, either the litterature to verify if anybody has ever done a Western with that protein (in the insect), or verify on the ab data sheet if it can be used on insect proteins (I have never seen such thing myself, but it could happen!)