天冬氨酸 谷氨酸 天冬酰胺 谷氨酰胺 Aspartate Glutamate Asparagine Glutamine (Asp, D) (Glu, E) (Asn, N) (GIn, Q) coo coo coo HN-C一H HBN-C-H HN=C一H H2N一C一H CH2 CH CH CH. CH CH. 0 NH 酸性氨基酸及其酰