Phosphomevalonic kinase pyrophosphomevalonic decarboxylase

Full details have appeared of the rubber enzyme phosphomevalonate kinase (EC 2.7.4.2) and 5-pyrophosphomevalonate decarboxylase (EC 4.1.1.33). 

The conversion of mevalonate (1) to isopentenyl pyrophosphate (IPP) (4) involves two consecutive phosphorylations at position 5 by successive action of mevalonate kinase (EC 2.7.4.2) and a decarboxylation and dehydration of the tertiary alcohol group by mevalonate 5-pyrophosphate decarboxylase (EC 4.1.1.33) (Fig. 18.4) (Crotean Johnson, 1985 Gershenzon and Croteau, 1990). One mole of ATP is required for each phosphorylation reaction. Mevalonate kinase converts mevalonic acid to (5/ )-phosphomevalonate (5). The second phosphorylation is catalyzed by phospho-mevalonate kinase. The subsequent decarboxylation and dehydration is mediated by the enzyme mevalonate diphosphate decarboxylase (di- or pyrophosphomevalonate decarboxylase EC 4,1.1.3.3) this enzyme requires Mg " or Mn + and ATP for activity (Beale and MacMillan, 1988 Harrison, 1988). All three of these enzymes are found in a number of plants. 

Tada, M., and Lynen, F. (1961). On the biosynthesis of terpenes. XIV. On the determination of phosphomevalonic acid kinase and pyrophosphomevalonic acid decarboxylase in cell extracts. J Biochem 49 758-764. 

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