Hydrolysis of geranyl pyrophosphate is catalyzed by salts of Mn2+ and involves C-O bond cleavage. The first order rate constants reach limiting values with [Mn2+] > 10−2 M, and the most reactive species is GPP(Mn2+)2 at the optimum pH of 6.5–7. The products are similar to those from acid hydrolysis except that more cyclic hydrocarbons are formed in the presence of metal ions. Hydrolysis of geranyl
BIOSYNTHESIS OF CYCLIC MONOTERPENOIDS. THE PIVOTAL ACYCLIC PRECURSOR FOR THE CYCLIZATION LEADING TO THE FORMATION OF α-TERPINEOL AND LIMONENE IN<i>MENTHA SPICATA</i>AND<i>CITRUS NATSUDAIDAI</i>
As a result of making a direct comparison among the incorporations of the pairs of 14C- and 3H-labeled linalyl, geranyl, and neryl pyrophosphates into α-terpineol and limonene in the cell-free extract of Mentha spicata and Citrus natsudaidai, respectively, the linalyl pyrophosphate was found to be the most pivotal, immediate precursor for the cyclization leading to the formation of the cyclic monoterpenoids.