Toby and I trashed the blood protein (8)
I believe the answer is:
antibody
'blood protein' is the definition.
'antibody' can be an answer for 'protein' (antibody is a kind of protein). I am unsure of the 'blood' bit.
'toby and i trashed' is the wordplay.
'trashed' indicates anagramming the letters.
'toby'+'and'+'i'='tobyandi'
'tobyandi' with letters rearranged gives 'ANTIBODY'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for antibody that I've seen before include "Protective protein in blood which destroys inimical substances" , "Fighter in blood" , "Protein produced in the blood" , "Pathogen fighter" , "protection against disease" .)