Why is chirality important in biochemistry?
1 Answer
Why? If someone stretches out their right hand to shake hands with you, can you shake their hand with your left hand?
Explanation:
The answer is NO, of course you cannot, even if you're a contortionist. Why not? Because of the chirality of your hand, or the handedness of left and right hands. Try it: right hands can clasp each other easily, as can left hands. Likewise, we can't slip a left glove over a right glove without turning one glove inside out (and inverting its chirality).
What we can appreciate on a macro scale with hands and gloves also operates on a molecular scale with sugars and proteins. Biological chemistry features a great deal of handedness: simple sugar is right-handed; left handed glucose is not metabolized. Why not? Because the biological enzymes that act on the glucose are themselves handed, and are not configured spatially to act on left-handed glucose, even if this isomer is chemically identical to its mirror image.