Showing papers on "Farnesyl pyrophosphate published in 1972"
TL;DR: Alternative mechanisms are proposed for the stereospecific elimination of the 4-pro-S proton of mevalonic acid in the biosynthesis of both cis and trans prenyl pyrophosphates.
32 citations
TL;DR: The stereochemical relationship between the added and abstracted hydrogen in the prototropic isomerization mediated by this enzyme is established and the chiral methyl groups formed on the enzyme isopentenyl pyrophosphate isomerase are established.
Abstract: Mevalonic acid stereospecifically labelled with tritium in the 2-position was incubated, in a deuterium oxide medium containing adenosine triphosphate, with a soluble enzyme preparation from pig liver; and so converted into farnesyl pyrophosphate. This was hydrolysed enzymically to farnesol which was oxidized, by ozone followed by sodium hypoiodite, to acetic acid originating from the terminal isopropylidene group of farnesol. The tritium in this acetic acid was found, on analysis by a recently developed enzymic method, to be present largely in chiral methyl groups the chirality of which was R or S according to the chirality at C-2 of the parent mevalonic acid. It is deduced that these chiral methyl groups were formed on the enzyme isopentenyl pyrophosphate isomerase, by addition of a deuteron from the medium to the 3 re, 4 re face of the double bond in isopentenyl pyrophosphate. The stereochemical relationship between the added and abstracted hydrogen in the prototropic isomerization mediated by this enzyme is thereby established. A preliminary communication of these results has been made (Clifford, Cornforth, Mallaby & Phillips 1971).
25 citations
TL;DR: Kinetic analysis with sonicated microsomal protein suspensions indicates that the reaction mechanism for the formation of squalene from farnesyl pyrophosphate is ping-pong and a partial scheme is proposed for the order of binding of substrates and release of products from the enzyme forms ofsqualene synthetase.
16 citations
TL;DR: The results define the manner of folding of the farnesyl pyrophosphate and exclude a γ-bisabolene intermediate in the biosynthesis and suggest that the carbonyl group of trichothecin might arise through the rearrangement of an epoxide.
Abstract: The incorporation of [2-3H2]-, (4R)-[4-3H]-, and [5-3H2]-mevalonate, [2-3H]geranyl pyrophosphate, and [1-3H2]-and [2-3H]-farnesyl pyrophosphate into the trichothecane nucleus is described. The results define the manner of folding of the farnesyl pyrophosphate and exclude a γ-bisabolene intermediate in the biosynthesis. The central prenyl (4R)-[4-3H]-label is retained in the biosynthesis and is transferred to C-2 of the trichothecane. The relative numbers of [2-3H2]- and [5-3H2]-mevalonoid labels that are incorporated suggest that the carbonyl group of trichothecin might arise through the rearrangement of an epoxide.
15 citations
TL;DR: Squalene synthetase, purified to near homogeneity from baker's yeast, has been resolved into two components of different molecular weight that catalyzes the first partial reaction of squalene synthesis, namely the formation of presqualene pyrophosphate.
14 citations
TL;DR: It is concluded that this insect is capable of isoprenoid biosynthesis at least to this point, and that the block in the cholesterol biosynthetic pathway lies beyond.
14 citations
TL;DR: In this paper, water soluble enzymes obtained from Pinus radiata seedlings form two sesquiterpene alcohols from 2- 14 C mevalonic acid, which have been identified as 2,6- trans,trans-farnesol and 2- cis,6-trans, 6-trans-francesol.
13 citations
TL;DR: 3-Ethylbut-3-enyl pyrophosphate acts as a substrate for farnesyl pyphosphate synthetase in place of isopentenylpyrophosphates to give farnesy pyroph phosphate homologues.
Abstract: 3-Ethylbut-3-enyl pyrophosphate acts as a substrate for farnesyl pyrophosphate synthetase in place of isopentenyl pyrophosphate, to give farnesyl pyrophosphate homologues.
12 citations
TL;DR: Sterol carrier protein from liver has been shown to bind the squalene precursor presqualene pyroph phosphate but not farnesyl pyrophosphate.
11 citations
10 citations