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. 1969 Feb;111(4):445–451. doi: 10.1042/bj1110445

Assay of the possible organization of particle-bound enzymes with squalene synthetase and squalene oxidocyclase systems

A H Etemadi 1,*, G Popják 1,†, J W Cornforth 1
PMCID: PMC1187563  PMID: 4388240

Abstract

Lanosterol was biosynthesized in pig liver homogenate from [4,8,12-14C3]farnesyl pyrophosphate and [4S-4-3H]NADPH through the intermediary formation of squalene labelled asymmetrically with 3H. The biosynthetic lanosterol, freed from labelled 24,25-dihydrolanosterol, which was also synthesized, was converted into 24,25-dihydrolanosteryl acetate and subjected to chemical degradations to locate the position(s) of the 3H label in the molecule. The ratio of 3H at C-11 to that at C-12 was found to be 1·28. Although a certain inequality of labelling was thus indicated, experimental uncertainties did not permit the conclusion that the asymmetrically labelled squalene might have been cyclized preferentially from one end.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. AVIGAN J., GOODMAN D. S., STEINBERG D. Studies of cholesterol biosynthesis. IV. Reduction of lanosterol to 24,25-dihydrolanosterol by rat liver homogenates. J Biol Chem. 1963 Apr;238:1283–1286. [PubMed] [Google Scholar]
  2. BUCHER N. L., MCGARRAHAN K. The biosynthesis of cholesterol from acetate-1-C14 by cellular fractions of rat liver. J Biol Chem. 1956 Sep;222(1):1–15. [PubMed] [Google Scholar]
  3. Cornforth J. W., Cornforth R. H., Donninger C., Popják G. Studies on the biosynthesis of cholesterol XIX. Steric course of hydrogen eliminations and of C-C bond formations in squalene biosynthesis. Proc R Soc Lond B Biol Sci. 1966 Jan 18;163(993):492–514. doi: 10.1098/rspb.1966.0004. [DOI] [PubMed] [Google Scholar]
  4. Donninger C., Popják G. Studies on the biosynthesis of cholesterol. 18. The stereospecificity of mevaldate reductase and the biosynthesis of asymmetrically labelled farnesyl pyrophosphate. Proc R Soc Lond B Biol Sci. 1966 Jan 18;163(993):465–491. doi: 10.1098/rspb.1966.0003. [DOI] [PubMed] [Google Scholar]
  5. POPJAK G., CORNFORTH J. W., CORNFORTH R. H., RYHAGE R., GOODMAN D. S. Studies on the biosynthesis of cholesterol. XVI. Chemical synthesis of 1-H2-3-2-C-14- and 1-D2-2-C-14-trans-trans-farnesyl pyrophosphate and their utilization in squalene biosynthesis. J Biol Chem. 1962 Jan;237:56–61. [PubMed] [Google Scholar]
  6. POPJAK G., GOODMAN W. S., CORNFORTH J. W., CORNFORTH R. H., RYHAGE R. Studies on the biosynthesis of cholesterol. XV. Mechanism of squalene biosynthesis from farnesyl pyrophosphate and from mevalonate. J Biol Chem. 1961 Jul;236:1934–1947. [PubMed] [Google Scholar]
  7. POPJAK G., SCHROEPFER G., CORNFORTH J. W. Sterospecificity of hydrogen transfer from reduced triphosphopyridine nucleotide to squalene during its synthesis from farnesyl pyrophosphate. Biochem Biophys Res Commun. 1962 Jan 24;6:438–442. doi: 10.1016/0006-291x(62)90371-6. [DOI] [PubMed] [Google Scholar]
  8. SAMUELSSON B., GOODMAN D. S. STEREOCHEMISTRY AT THE CENTER OF SQUALENE DURING ITS BIOSYNTHESIS FROM FARNESYL PYROPHOSPHATE AND SUBSEQUENT CONVERSION TO CHOLESTEROL. J Biol Chem. 1964 Jan;239:98–101. [PubMed] [Google Scholar]
  9. TCHEN T. T., BLOCH K. On the conversion of squalene to lanosterol in vitro. J Biol Chem. 1957 Jun;226(2):921–930. [PubMed] [Google Scholar]

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