Fig. 1: Levels of aspartate and serine enantiomers in human serum.

d- and l-Asp (A, left and center, respectively) and d- and l-Ser (B, left and center, respectively) levels and ratio between d-enantiomer and total (d+l) amino acid content (A, right, and B, right for Asp and Ser, respectively, expressed as percentage) detected in serum samples of AD patients compared to healthy subjects (HS). Dots and bars represent the single subjects’ values and the standard error of the mean, respectively. **P < 0.01 (Mann–Whitney unpaired test).