Monkey blood protein found in powder he's using (6)
I believe the answer is:
rhesus
'monkey blood protein' is the definition.
'rhesus' can be an answer for 'monkey' (I've seen this before). I am unsure of the 'blood protein' bit.
'in powder he's using' is the wordplay.
'in' indicates a hidden word.
'RHESUS' is hidden in the letters of 'powder hes using'.
'found' acts as a link.
Can you help me to learn more?
(Other definitions for rhesus that I've seen before include "Monkey - factor in blood cell problem" , "King, in Greek mythology" , "(Kind of monkey) used in medical experiments" , "Monkey and blood element" , "Small Asian macaque" .)