Let new enzyme at last inside cheese-maker's additive (6)
I believe the answer is:
rennet
'cheese-maker's additive' is the definition.
I can't judge whether this definition defines the answer.
'let new enzyme at last inside' is the wordplay.
'let' becomes 'rent' (synonyms).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'at last' indicates one should take the final letters.
'inside' is an insertion indicator.
The final letter of 'enzyme' is 'e'.
'n'+'e'='ne'
'rent' enclosing 'ne' is 'RENNET'.
Can you help me to learn more?
(Other definitions for rennet that I've seen before include "substance used for curdling" , "Substance that curdles milk" , "Dairy compound" , ""This has turned the milk!"" , "Cheesemakers use this" .)