Two chiral catalysts working hand in hand
(PHYSorg.com Chemistry)

Just as our left hand is not superposable to our right hand, the mirror image of certain molecules cannot be overlapped onto it, even when turned or twisted. These two mirror images are referred to by chemists as enantiomers and the molecule is said to be chiral. Chirality, which is a word derived from the ancient Greek word for hand, is important since it is present in our daily lives. For example, the stereoisomers of a molecule-i.e. compounds in which the binding pattern is the same but which differ in the spatial arrangement of the atoms-can produce different effects when interacting with a biological system.