Principles of Biochemistry (2+1)

4.2.3 Optical activity

The tetrahedral orientation of four different groups about the ∝ carbon atom confers optical activity on amino acids. It is the ability to rotate the plane of plane-polarized light.

Except glycine, each amino acids has at least one asymmetric carbon atom and hecnce is optically active. Some amino acids found in proteins are dextrorotatory (+) and some levorotatory (-) at pH 7.0