INTERCONVERSION AND CYCLIZATION OF ACYCLIC ALLYLIC PYROPHOSPHATES IN THE BIOSYNTHESIS OF CYCLIC MONOTERPENOIDS IN HIGHER PLANTS

Article abstract of DOI:10.1016/S0031-9422(00)83738-3

Key Word Index - Biosynthesis; interconversion; cyclization; acyclic allylic pyrophosphates; cyclic monoterpenoids; higher plants.The biosynthesis of cyclic monoterpenoids has been investigated in both intact plants and cell-free extracts of several higher plants.The participation of a non-redox process in the biosynthesis of the cyclic monoterpenoids was indicated by the retention of all the tritium labels originating from <2-14C,5-3H2>mevalonic acid and <1-14C,1-3H2>geranyl, neryl and linalyl pyrophosphates.The cell-free extract catalysed the non-redox interconversions of geranyl, neryl and linalyl pyrophosphates to each other.By contrast, in both intact plants and cell-free extracts, the incorporation of linalyl pyrophosphate into the cyclic monoterpenoids occurred preferentially to the incorporation of neryl and geranyl pyrophosphates.These observations suggest the involvetment of a teriary allylic compound and/or its equivalent as a key intermediate, not only in the interconversion of the acyclic allylic pyrophosphates, but also in the formation of the cyclic monoterpenoids.