Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1969 Oct;114(4):885–892. doi: 10.1042/bj1140885

Incorporation of [2-14C,(5R)-5-3H1]mevalonic acid into cholesterol by a rat liver homogenate and into β-sitosterol and 28-isofucosterol by Larix decidua leaves

L J Goad 1, G F Gibbons 1, Loretta M Bolger 1, H H Rees 1, T W Goodwin 1
PMCID: PMC1184980  PMID: 5348842

Abstract

1. Incubation of a rat liver homogenate with 3R-[2-14C,(5R)-5-3H1]mevalonic acid gave cholesterol with 3H/14C atomic ratio 6:5. 2. Conversion of the labelled cholesterol into 3β-acetoxy-6-nitrocholest-5-ene or cholest-4-ene-3,6-dione resulted in the loss of one tritium atom from C-6. 3. These results show that during cholesterol biosynthesis the 6α-hydrogen atom of a precursor sterol is eliminated during formation of the C-5–C-6 double bond. 4. Incorporation of 3R-[2-14C,(5R)-5-3H1]mevalonic acid into the sterols of larch (Larix decidua) leaves gave labelled cycloartenol and β-sitosterol with 3H/14C atomic ratios 6:6 and 6:5 respectively. 5. One tritium atom was lost from C-6 on conversion of the labelled β-sitosterol into either 3β-acetoxy-6-nitrostigmast-5-ene or stigmast-4-ene-3,6-dione, demonstrating that formation of the C-5–C-6 double bond of phytosterols also involves the elimination of the 6α-hydrogen atom of a precursor sterol. 6. The 3R-[2-14C,(5R)-5-3H1]mevalonic acid was also incorporated by larch (L. decidua) leaves into a sterol that co-chromatographed with 28-isofucosterol. Confirmation that the radioactivity was associated with 28-isofucosterol was obtained by co-crystallization with carrier 28-isofucosterol and ozonolysis of the acetate to give radioactively labelled 24-oxocholesteryl acetate. 7. The significance of these results to phytosterol biosynthesis is discussed.

Full text

PDF
885

Selected References

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

  1. Akhtar M., Marsh S. The stereochemistry of the hydrogen elimination in the biological conversion of cholest-7-en-3-beta-ol into cholesterol. Biochem J. 1967 Feb;102(2):462–467. doi: 10.1042/bj1020462. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Akhtar M., Parvez M. A. The mechanism of the elaboration of ring B in ergosterol biosynthesis. Biochem J. 1968 Jul;108(4):527–531. doi: 10.1042/bj1080527. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Akhtar M., Rahimtula A. D., Watkinson I. A., Wilton D. C., Munday K. A. The status of C-6, C-7, C-15 and C-16 hydrogen atoms in cholesterol biosynthesis. Eur J Biochem. 1969 May 1;9(1):107–111. doi: 10.1111/j.1432-1033.1969.tb00582.x. [DOI] [PubMed] [Google Scholar]
  4. 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]
  5. 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]
  6. Dempsey M. E. Pathways of enzymic synthesis and conversion to cholesterol of delta-5,7,24-cholestatrien-3 beta-ol and other naturally occurring sterols. J Biol Chem. 1965 Nov;240(11):4176–4188. [PubMed] [Google Scholar]
  7. Dewhurst S. M., Akhtar M. The conversion of cholest-7-en-3beta-ol into cholesterol. General comments on the mechanism of the introduction of double bonds in enzymic reactions. Biochem J. 1967 Dec;105(3):1187–1194. doi: 10.1042/bj1051187. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. 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]
  9. Goad L. J., Goodwin T. W. Studies on phytosterol biosynthesis: the sterols of Larix decidua leaves. Eur J Biochem. 1967 May;1(3):357–362. doi: 10.1007/978-3-662-25813-2_49. [DOI] [PubMed] [Google Scholar]
  10. Goad L. J., Goodwin T. W. The biosynthesis of sterols in higher plants. Biochem J. 1966 Jun;99(3):735–746. doi: 10.1042/bj0990735. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Goad L. J., Hammam A. S., Dennis A., Goodwin T. W. Biosynthesis of the phytosterol side chain. Nature. 1966 Jun 25;210(5043):1322–1324. doi: 10.1038/2101322a0. [DOI] [PubMed] [Google Scholar]
  12. Lederer E. The origin and function of some methyl groups in branched-chain fatty acids, plant sterols and quinones. Biochem J. 1964 Dec;93(3):449–468. doi: 10.1042/bj0930449. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Paliokas A. M., Schroepfer G. J., Jr Stereospecificity in the enzymatic conversion of delta-7-cholesten-3-beta-ol to 7-dehydrocholesterol. J Biol Chem. 1968 Feb 10;243(3):453–464. [PubMed] [Google Scholar]
  14. Patterson G. W., Karlander E. P. Fucosterol Reduction to Clionasterol in vivo by Chlorella ellipsoidea. Plant Physiol. 1967 Nov;42(11):1651–1652. doi: 10.1104/pp.42.11.1651. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Popják G., Cornforth J. W. Substrate stereochemistry in squalene biosynthesis: The first Ciba medal lecture. Biochem J. 1966 Dec;101(3):553.b4–553568. [PMC free article] [PubMed] [Google Scholar]
  16. Rees H. H., Goad L. J., Goodwin T. W. Studies in phytosterol biosynthesis. Mechanism of biosynthesis of cycloartenol. Biochem J. 1968 Apr;107(3):417–426. doi: 10.1042/bj1070417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. 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]
  18. SCHWENK E., WERTHESSEN N. T. Studies on the biosynthesis of cholesterol. III. Purification of C14-cholesterol from perfusions of livers and other organs. Arch Biochem Biophys. 1952 Oct;40(2):334–341. doi: 10.1016/0003-9861(52)90119-7. [DOI] [PubMed] [Google Scholar]
  19. Williams R. J., Britton G., Charlton J. M., Goodwin T. W. The stereospecific biosynthesis of phytoene and polyunsaturated carotenes. Biochem J. 1967 Sep;104(3):767–777. doi: 10.1042/bj1040767. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Wilton D. C., Munday K. A., Skinner S. J., Akhtar M. The biological conversion of 7-dehydrocholesterol into cholesterol and comments on the reduction of double bonds. Biochem J. 1968 Feb;106(4):803–810. doi: 10.1042/bj1060803. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. van Aller R. T., Chikamatsu H., de Souza N. J., John J. P., Nes W. R. The metabolic role of the 24-ethylidenecholesterols. Biochem Biophys Res Commun. 1968 Jun 10;31(5):842–844. doi: 10.1016/0006-291x(68)90640-2. [DOI] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES