Protein — all but mine never-ending! (7)

I believe the answer is:

albumin

I'm a little stuck... Click here to teach me more about this clue!

'protein' is the definition.
(albumin is a kind of protein)

I don't understand how the rest of the clue works.

(Another definition for albumin that I've seen is " Protein".)

I've seen this clue in The Hindu.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.