Catalyst 'Z' in Yemen reprocessed (6)
I believe the answer is:
enzyme
'catalyst' is the definition.
(enzyme is a kind of catalyst)
'z in yemen reprocessed' is the wordplay.
I cannot really see how this works, but
'z' is found in the answer.
an anagram of 'yemen' is 'enyme' which is located in the left over letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for enzyme that I've seen before include "Protein substance acting as a catalyst" , "E.g. pepsin" , "causing ferment" , "It acts as a catalyst to bring about biochemical reaction" , "Biochemical catalyst produced in the body" .)