穀氨酸
The carbon atom adjacent to the amino group is chiral (connected to four distinct groups). Glutamic acid can exist in three optical isomers, including the dextrorotatory -form, (−), and (+). The form is the one most widely occurring in nature, but the form occurs in some special contexts, such as the cell walls of the bacteria (which can manufacture it from the form with the enzyme glutamate racemase) and the liver of mammals.