1-Deoxy-D-xylulose-5-phosphate 1 or the corresponding nonphosphorylated sugar, 2, has been identified as a precursor in three major biosynthetic pathways (Scheme 1). In higher plants, algae, and bacteria, a nonmevalonate pathway to isopentenyl diphosphate 3 which utilizes 1 or 2 has been demonstrated. 1 In bacteria, 1 or 2 is involved in the biosynthesis of thiamin pyrophosphate 4. 2 In Escherichia coli, it has been demonstrated that one of the ...