[...]
Quantum rules are thought to break down and give way to the classical world as things get bigger. But enzymes are small, and move their substrate particles over short distances. David Leys, Nigel Scrutton, Michael Sutcliffe and colleagues at Manchester University, together with Adrian Mulholland at Bristol, have just published a paper in the journal Science that claims that an enzyme called aromatic amine dehydrogenase (AADH) accelerates its chemical reaction by bringing the substrate particles so close to the enzyme that the fog of particle positions overlaps, allowing a proton to "quantum tunnel" from substrate to enzyme.
That biochemical reactions involve quantum tunnelling isn't surprising, since tunnelling also happens in some inorganic reactions. But in the case of AADH, the enzyme isn't just capturing a process that occurs anyway, the dynamics of the enzyme actively promote the quantum tunnelling event in order to accelerate the reaction rate. The enzyme needs quantum mechanics to work.
Leys'
research implies that enzymes have evolved to dip into the weird world
of quantum mechanics to enhance reaction rates. This indicates that the
motive force driving bird flight and a million other biological
processes depends on quantum tunnelling. If true, then quantum
tunnelling has been central to life since its inception: life may have
discovered 21st-century quantum technology billions of years ago.
Quantum mechanics may be what makes life so special - the weird rules
of the very small writ large in the world.
http://www.guardian.co.uk/commentisfree/story/0,,1791275,00.html
