STRUCTURE AND BIOSYNTHESIS OF TRANS-POLYISOPRENE FROM EUCOMMIA ULMOIDES

The structure of trans-polyisoprene from both bark and leaves of Eucom mia ulmoides was analysed by H-1 NMR and C-13 NMR. Both spectra showed characteristic signals of the dimethylallyl-group, as well as termina l ester and diphosphate groups. The degree of polymerization estimated from the intensity ratio of signals from the internal trans-units and the dimethylallyl-group was in fair agreement with that determined by osmometry. The trans-polyisoprene from E. ulmoides is a high molecula r-weight homologue of solanesol, consisting of the dimethylallyl-group , 60-3000 internal trans-units, and a terminal aliphatic fatty acid es ter-group or a diphosphate group, aligned in that order. (C) 1997 Else vier Science Ltd.