3.4- Dihydroxy-3-methyl-pentanoic

Mevalonic acid [(MVA, (/f)-3,5-dihydroxy-3-methyl-pentanoic acid, hiochic acid]. 

Dihydroxyacid dehydratase of the branched-chain amino acid biosynthetic pathway catalyzes the dehydration and tautomerization of 2,3-dihydroxy-3-methyl-(butyrate and pentanoate) to 2-keto-3-methyl(butyrate and pentanoate). The enzyme isolated from spinach recently has been shown to have not a [4Fe-4S] cluster, but rather a spectroscopically unusual [2Fe-2S] cluster in its active site (68,69). The EPR spectrum of the reduced enzyme is similar to that seen for Rieske Fe-S proteins (71) with a g-average of 1.91. Upon addition of substrate the g-average of the EPR spectrum shifts to 1.96 (opposite the effect of substrate on aconitase), and then reverts back to a g-average of 1.90 when only the product is present The dramatic changes in the EPR spectra upon addition of substrate suggest, in analogy to aconitase, that the Fe-S cluster may be directly involved in catalysis. 

Pentanoic acid, 3,5-dihydroxy-5-methyl- mevalonic acid) 3973 ... 

Figure 31 Mass fragmentogram of methyl bis(trifluoroacetates) of DL-pantothenic acid and DL-hopantenic acid. Column fused sihca capillary, 20 m X 0.22 mm, film thickness 0.12 fim stationary phase Chirasil-D-Val coated with L-valine-terr-hutylamide mobile phase helium, 1 kg/cm split ratio 1 30 temperatures injector 180°C, column 130°C, separator 250°C, ion source 250°C detector not specified ions miz 257, 271, and 285 peak identification (1) L-pantothenic acid (2) D-pantothenic acid (3) L-hopantenic acid (4) D-hopantenic acid (5) D-5-[2,4-dihydroxy-3,3-dimethyl-l-oxobutylamino]pentanoic acid (internal standard). (From Ref. 56.)...

Estradiol is the actual ovarian follicular hormone. It is a colourless steroid, slightly soluble in water, but freely soluble in organic solvents. Chemically, it is the 3 4-dihydroxy derivative of oestrane, or 13-methyl cydo-pentano phenanthrene, the mono-methylated steroid nucleus which occurs in all the natural oestrogens (p. 172). (Estrone and oestiiol represent various oxidation... 

---