Yes, PROENZYMES is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, E 1, N 1, Z 10, Y 4, M 3, E 1, S 1.

Is it a valid word?

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

any of a group of compounds that are inactive precursors of enzymes and require some change (such as the hydrolysis of a fragment that masks an active enzyme) to become active