Yes, PERTURBS is a Scrabble word!

Letter values in Scrabble US: P 3, E 1, R 1, T 1, U 1, R 1, B 3, S 1.

Is it a valid word?

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

disturb in mind or make uneasy or cause to be worried or alarmed
disturb or interfere with the usual path of an electron or atom
cause a celestial body to deviate from a theoretically regular orbital motion, especially as a result of interposed or extraordinary gravitational pull
throw into great confusion or disorder

Also: throw out of kilter.