Isoprenoid Enzyme Systems of Silkworm. I. Partial Purification of Isopentenyl Pyrophosphate Isomerase, Farnesyl Pyrophosphate Synthetase, and Geranylgeranyl Pyrophosphate Synthetase1

Abstract

Isopentenyl pyrophosphate isomerase, farnesyl pyrophosphate synthetase, and geranylgeranyl pyrophosphate synthetase were detected in cell-free extracts of Bombyx mori and were partially purified by hydroxyapatite and Sephadex G-100 chromatography. Two forms of farnesyl pyrophosphate synthetase were chromatographically separated. They were designated as farnesyl pyrophosphate synthetases I and II in the order of their elution from hydroxyapatite. Both enzymes catalyzed the exclusive formation of (E,E)-farnesyl pyrophosphate from isopentenyl pyrophosphate and either dimethylallyl pyrophosphate or geranyl pyrophosphate. However, they were not interconvertible, unlike the enzyme from pig liver. These two enzymes resembled each other in pH optima and molecular weights but differed in susceptibility to metal ions. Farnesyl pyrophosphate synthetase II was stimulated by Triton X-100 while synthetase I was inhibited by the same reagent.

Prenyltransferase of larval and adult M. sexta corpora allata

“…These results are consistent with prior studies in Bombyx mori, where two distinct FPPSs were purified from whole body preparations (Koyama et al, 1985). In addition, both B. mori and another lepidopteran insect Pseudaletia unipuncta are known to possess at least two structurally distinct (Type I and Type II) FPPSs (Cusson et al, 2006).…”

“…In plants, multiple isoforms of FPPS are known to be under developmental regulation (Cunillera et al, 1996;Hemmerlin et al, 2003), and FPPS is one of several enzymes that regulate sterol levels in vertebrates (Goldstein and Brown, 1990). In insects, two FPPS (FPPS I and II) from whole body preparations of Bombyx mori are known (Koyama et al, 1985), and a distinct FPP synthase from larval Manduca sexta has been purified and characterized (Sen and Sperry, 2002). But based on the small size of the corpora allata (CA) relative to other tissues, insect FPPS identified from prior studies may not be related to those directly involved in JH biosynthesis.…”

Squalene epoxidase (SQLE) promotes the growth and migration of the hepatocellular carcinoma cells

“…Taken together, these observations suggested that SQLE promoted cell growth and migration through activating mevalonate pathway, and targeting cholesterol synthesis pathway will provide a promising therapeutic approach. The modification of numerous proteins with farnesyl and geranylgeranyl isoprenoid groups is very important for cell growth, and most of the farnesyl and geranylgeranyl isoprenoid groups are derived from the metabolism of mevalonate [21,22]. Statin acts as the agents to lower plasma cholesterol levels by inhibiting the activity of HMG-CoA reductase [23,24].…”

Control of juvenile hormone biosynthesis in Bombyx mori: Cloning of the enzymes in the mevalonate pathway and assessment of their developmental expression in the corpora allata

“…Two different forms of FPPS (''FPPS I'' and ''FPPS II'') were partially purified by Koyama et al (1985a) from whole larvae of Bombyx (without silk glands and guts), and ''FPPS II'' appeared better suited than ''FPPS I'' for the synthesis of the carbon skeletons of ethyl-substituted JHs, based on its relative activity in the presence of homologous substrates (Koyama et al, 1985b). Whether or not these FPPSs correspond to two of the three FPPSs we cloned is unknown, but Koyama et al (1985b) argued that it was unlikely that their ''FPPS II'' was localized only in the CA, because the amount enzyme extracted was too large for it to be derived only from the small CA.…”