1 SZ8 Methyl (4r)-4-amino-1-methyl-L-prolinate 1.000 2 PDW Methyl D-prolinate 0.818 3 PLJ Methyl L-prolinate 0.818 4 PYB 4-amino-(1-methylpyrrole)-2-carboxylic acid 0.750 5 U29 Methyl (5s)-1-acetyl-5-methyl-L-prolinate 0.714