trans Reduction of .DELTA.24 of lanosterol in the biosynthesis of cholesterol by rat liver enzymes

Caspi, E.; Mg, Kienle; Kr, Varma; Lj, Mulheirn

doi:10.1021/ja00710a075

Cited by 11 publications

(6 citation statements)

References 2 publications

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“…Because the geometry at 24 of lanosterol8 is as in 1, we inferred that the reduction of 24 entails a trans addition of two hydrogens. 6 We noted that our conclusions are at variance with the situation in tigo-genin6 and were in contrast with recent observations of Professors Ch. Tamm and D. Arigoni on the biosynthesis of sapogenins in D. lanata?…”

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confidence: 99%

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Novel chemiluminescence observed on electroreduction of aromatic hydrocarbons in the presence of some alkyl halides

Siegel¹,

Mark²

1971

J. Am. Chem. Soc.

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confidence: 99%

“…The synthetic 25R and 25S speci- 0 Measured using a Hilger MKIII polarimeter. 6 Measured using an O. C. Rudolph and Sons, Inc., photoelectric polarimeter with oscillating polarizer. ' Hydroboration of cholest-5,26dien-3/3-ol.…”

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confidence: 99%

Novel chemiluminescence observed on electroreduction of aromatic hydrocarbons in the presence of some alkyl halides

Siegel¹,

Mark²

1971

J. Am. Chem. Soc.

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“…which is stabilized via the loss of a C-19 hydrogen to yield cycloartenol19 (11). It is presumed that 10 is transiently stabilized by a 9a prosthetic group.19 Al-ternatively, loss of a C-ll hydrogen will result in parked (12).…”

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confidence: 99%

Biosynthesis of tetrahymanol by Tetrahymena pyriformis: mechanistic and evolutionary implications

Caspi¹

1980

Acc. Chem. Res.

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Polyprenoids constitute a diverse, widely distributed group of natural products derived biologically from (3fi)-mevalonic acid1,2 (1). Based on geochemical3 and other studies,4 it was inferred that the biosynthetic processes of polyprenoids evolved in the very early stages of evolutionary development.5,6 Although polyprenoids play a vital role in numerous life processes, e.g., as sex or corticosteroidal hormones, as bile acids, in vision, in defense mechanisms, etc., it appears that their primary biological function is to provide a structural component(s) of cell membranes.6Many eucaryotes, and particularly higher species, produce a variety of 3-oxygenated triterpenes and sterols.1,2 The 3-oxygenated triterpenes are derived from squalene1,2 (2) which is converted to 2,3(5)-oxidosqualene7 (3). The enzymatic cationic cleavage of the oxygen-C-2 bond of 3 generates an electron deficiency at C-2 and precipitates the cyclization process. Depending on the characteristics of the enzyme system of the particular species, different products may be formed.1,2,8,9 In Fusidium coccineum, cyclization10 of 3 is presumed to result in the cation8 4a or its transiently stabilized equivalent9,11 4b, which loses the C-17 proton12 to yield the parent protosterol13 (5). The protosterol13 ( 5) is then further metabolized to fusidic acid (6). This hypothesis is supported by the results of studies on the mode of incorporation of C-2,12,14 C-4,11 and C-515 hydrogen atoms of MVA into 6 and by the

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“…Sih and Wang (8) and later Afonso et al (1) employed 19-hydroxylated and 19-nor derivatives, respectively, to produce estrone via the microbial degradation of the cholesterol-type side chain and aromatization of the steroid A ring. Further modification of the basic sterol structure to 6,19-oxido (W. F. van der Waard, U.S. Patent 3,487,907,1970; C. J. Sir, U.S. Patent 3,507,749, 1970) or 3a,5-cyclo-6f, 19oxido derivatives (M. Shirasaka et al, U.S. Patent 3,475,275, 1969) protects the ring sys-72 stem from decomposition while permitting sidechain degradation to the 17-ketone.…”

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confidence: 99%

Microbial Degradation of Sterols

Marsheck¹,

Kraychy²,

Muir³

1972

Applied Microbiology

142

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A process is described for the microbial degradation of cholesterol and plant sterols, to produce androsta-1, 4-diene-3, 17-dione and androst-4-ene-3, 17dione, by two newly isolated bacteria designated Mycobacterium sp. NRRL B-3683 and Mycobacterium sp. NRRL B-3805. These myocbacteria produce substantial amounts of 17-ketonic compounds without appreciable degradation of the steroid nucleus. No ring degradation inhibitory agents are necessary. The first microbiological production of 20a-hydroxymethylpregna-1,4-dien-3-one is also reported.

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trans Reduction of .DELTA.24 of lanosterol in the biosynthesis of cholesterol by rat liver enzymes

Cited by 11 publications

References 2 publications

Novel chemiluminescence observed on electroreduction of aromatic hydrocarbons in the presence of some alkyl halides

Novel chemiluminescence observed on electroreduction of aromatic hydrocarbons in the presence of some alkyl halides

Biosynthesis of tetrahymanol by Tetrahymena pyriformis: mechanistic and evolutionary implications

Microbial Degradation of Sterols

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