Artificial substrates for undecaprenyl diphosphate synthase from Micrococcus luteus B-P 26

Substrate specificity of undecaprenyl diphosphate synthase of Micrococcus luteus B-P 26 was investigated with respect to some alkyl- and bromo-group homologs of isopentenyl diphosphate. Among the homologs relating to the 3-methyl group, but-3-enyl diphosphate (2b) and 3-ethylbut-3-enyl diphosphate (3b) were accepted as substrates, with (all-E)-farnesyl diphosphate (FPP) to give 7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl diphosphate, and a mixture of 3-ethyl-7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl- and 3,7-diethyleicosa-2,6,10,14,18-pentaenyl diphosphates, respectively. With respect to the homologs modified at the 4 position of isopentenyl diphosphate, (4E)-3-methylpent-3-enyl diphosphate (2f) was accepted as a substrate to give (4S)-(2Z,6E,10E,14E)-4-methylgeranylgeranyl- and (4S,8S)-(2Z,6Z,10E,14E,18E)-4,8-dimethylgeranylfarnesyl diphosphates. Neither (4Z)-3-methylpent-3-enyl diphosphate nor 4-bromo-3-methylbut-3-enyl diphosphates was accepted as a substrate at all.