Yes, UBIQUINONE is a Scrabble word!

Letter values in Scrabble US: U 1, B 3, I 1, Q 10, U 1, I 1, N 1, O 1, N 1, E 1.

Is it a valid word?

UBIQUINONE is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

any of several quinones found in living cells and that function as coenzymes that transfer electrons from one molecule to another in cell respiration

Also: coenzyme q.