Nevertheless, the idea that protons as well as electrons can quantum tunnel is a striking one.

ECONOMIST: Biochemistry: Evolving enzymes | The

But protons are far bigger, and the idea that they might be able to quantum tunnel is more controversial.

ECONOMIST: Biochemistry: Evolving enzymes | The

They argue that this happens because the enzymes move in such a way that it becomes possible for protons to quantum tunnel.

ECONOMIST: Biochemistry: Evolving enzymes | The