British scientists have found that enzymes cheat time and space by quantum tunnelling - a much faster way of travelling than the classical way - but whether or not perplexing quantum theories can be applied to the biological world is still hotly debated.

Until now, no one knew just how the enzymes speed up the reactions, which in some cases are up to a staggering million times faster.

"Our research has shown at an atomic level how enzymes act as catalysts," said Nigel Scrutton, lead researcher at the University of Manchester.

Just how these enzymes speed up reaction rates compared with uncatalysed reactions remain controversial among scientists, but such insights of the underpinnings of enzyme behaviour have begun.

"Enzymes are central to the existence of life because most chemical reactions in our cells would take place too slowly or produce a difference outcome without their involvement," he said.

Without enzymes, we'd wither away or be riddled with disease.

As biological molecules, the enzymes work to lower the energy needed for a reaction to occur. Although enzymes act as catalysts, they are often affected by other molecules. Therefore, when drugs are made, they are designed to act as enzymes inhibitors to stop the reactions from occurring.

"The findings are a radical departure from the traditional view of how they work and might explain why attempts to make artificial enzymes have so far been disappointing," he said.

But now that researchers know enzymes can quantum tunnel, better drugs can be designed leveraging this knowledge.

The scientists used a widespread neurotransmitter, called tryptamine, in their experiments. This compound is stable because it has nitrogen and two hydrogen atoms attached to a ring of carbons.

The quantum tunnelling was seen when the otherwise tightly-bound hydrogen atom was set free. In this case, if the hydrogen is given the choice to climb the mountain or walk through the tunnel, it chose the one that required less energy: the tunnel. But this quantum leap only happens when the nearby motions allow it to traverse this easier, less-exhausting path.

"The work suggests that tunnelling in this enzyme, which we find to be central to the reaction it catalyses, is driven by subtle changes of conformation confined to the active site - and that longer-range dynamics changes of the protein apparently play no part in the process," said collaborator Adrian Mullholland of University of Bristol.

"The findings have sparked a keen debate among biologists about the fundamental nature of enzymes," Mullholland said, with the results published in the June issue of Science.

However in the same issue of Science Stephen Benkovic and Sharon Hammes-Schiffer of Pennsylvania State University contest that the long-range motions need to be considered because the whole process is more complex than the theory considers.

"This paradigm shift away from standard 'over the barrier' textbook models of enzyme catalysis to a 'through the barrier' model provides new experimental challenges to the field," Scrutton said.

A critical and perplexing question is at what point does the bizarre world of quantum theory give way to the everyday world of large objects.

Any object from the size of an atom to even the size of a human has a wave function according to quantum mechanics. But smaller objects (often nanoscale sized) have a more noticeable wave function, detectable only by experimental means.

Using an interdisciplinary approach, the scientists used X-ray crystallography, nuclear magnetic resonance, computational chemistry, protein engineering, and sophisticated kinetic and spectroscopic methods, to observe the waves of the hydrogen.

Either way, the findings are a step closer towards "improving our fundamental knowledge of how enzymes work," he said.

But sometimes the laws that govern the physical world cannot be cheated, and understanding rarely happens in quantum leaps.