The D-L system corresponds to the configuration of the molecule and the spatial arrangement of its atoms around the chirality center. The D-L configuration is not to be confused with the d- l- naming which means dextrorotatory and levorotatory respectively. (+) and (-) notation corresponds to the optical activity of the substance, whether it rotates the plane polarized light clockwise (+) or counterclockwise (-). So, D(+) – glucose is dextrorotatory in nature but ‘D’ does not represent its dextrorotatory nature.