THE BIOSYNTHESIS OF TROPIC ACID - THE (R)-D-PHENYLLACTYL MOIETY IS PROCESSED BY THE MUTASE INVOLVED IN HYOSCYAMINE BIOSYNTHESIS IN DATURA-STRAMONIUM

Incubations of (R)-D-phenyl[2-C-13,H-2]lactic acid 5a and (S)-L-phenyl[2-C-13,H-2]lactic acid 5b with transformed root cultures of Datura stramonium have revealed that the C-13-H-2 bond is retained, intact at C-3 of the tropate moiety of hyoscyamine, only in the case of the (R)-D enantiomer 5a (the deuterium is lost from the (S)-L-enantiomer 5b); therefore, it is the (R)-D-phenyllactate moiety of littorine which is the enantiomer processed by the mutase in hyoscyamine biosynthesis.