STOCKHOLM (Reuters) - Two American scientists won the 2012 Nobel Prize for chemistry for groundbreaking work on a key family of receptors which enable cells to sense their environment, the prize committee said on Wednesday.

The Royal Swedish Academy of Sciences said in a statement the 8 million crown ($1.2 million) prize went to Robert Lefkowitz and Brian Kobilka for discovering the inner workings of G-protein-coupled receptors.

Chemistry was the third of this year's Nobel prizes. Prizes for achievements in science, literature and peace were first awarded in 1901 in accordance with the will of dynamite inventor and businessman Alfred Nobel.

(Editing by Patrick Lannin and Alistair Scrutton)