Mevalonate-metabolizing enzymes in Arachis hypogaea

Abstract

The activities of the mevalonate metabolizing enzymes-HMG-CoA reductase, mevalonate kinase, mevalonate phosphokinase and mevalonate pyrophosphate decarboxylase -were assayed with the respective substrates in green seedlings of Arachis hypogaea. MVAPP decarboxylase is the rate-limiting step among these enzymes and is inhibited by phenolic acids. Its activity in the seedlings was found to decrease in the absence of light and on treatment with abscisic acid. These results suggest that regulation of isoprene pathway in groundnut seedlings may occur at the level of mevalonate decarboxylation.

Herbicide Clomazone Does Not Inhibit In Vitro Geranylgeranyl Synthesis from Mevalonate

“…These enzymes produce MVAP, MVAPP, and IPP (2). MVAPP decarboxyl- ase (EC 4.1.1.33) has been shown to be the rate-limiting step among these three enzymes and is inhibited by phenolic acids (10). However, clomazone showed no effect on the production of IPP from MVA ( Fig.…”

Overexpression, Purification, and Characterization of the Thermostable Mevalonate Kinase from Methanococcus jannaschii

“…Although mevalonate kinase has been widely described in yeast (15), animals (16,17), and plants (18,19), very little is known about this enzyme in microorganisms and archaeon. Methanococcus jannaschii (20) was the first completely sequenced archae; it grows at pressure of up to 200 atm and over a temperature range of 48 to 94°C, with an optimum temperature near 85°C.…”

Biosynthesis of C5–C20terpenoid compounds

“…Activities of this enzyme, as well as those of the preceding enzymes mevalonate kinase and mevalonate phosphokinase, have been examined in seedlings of the groundnut, Arachis hypogaea. 28 Anderson et al 29 have reported the isolation of the gene encoding isopentenyl diphosphate : dimethylallyl diphosphate isomerase, the next enzyme of the terpenoid pathway. Enzyme was purified from yeast and N-terminal sequenced.…”

“…This indicates that the mechanism depicted in Scheme 9, via initial cyclization of FPP to the 10-membered germacryl ring system, is operative. Last year it was suggested that 5-epi-aristolochene (27) was a precursor to the phytoalexins capsidiol (28) and debneyol (29) in cellulase-elicited cell cultures of Nicotiana tabacurn. Whitehead et have now confirmed their earlier suggestions by isolation of (27) from cultures in which hydroxylation is inhibited by exclusion of oxygen or NADPH.…”