Yes, PURINES is a Scrabble word!

Letter values in Scrabble US: P 3, U 1, R 1, I 1, N 1, E 1, S 1.

Is it a valid word?

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

any of several bases that are derivatives of purine
a colorless crystalline organic base containing nitrogen; the parent compound of various biologically important substances