Continue feeding a German protein (7)

I believe the answer is:

elastin

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

'continue feeding a german' is the wordplay.
'continue' becomes 'last' (I've seen this before).
'feeding' means one lot of letters goes inside another.
'a german' becomes 'ein' ('a' in German).
'last' going inside 'ein' is 'ELASTIN'.

(Another definition for elastin that I've seen is " protein".)

I've seen this clue in The Independent.

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