Multiple Roles for Plant Sterols
In certain ways all sterols are the same, yet in other respects they are quite different. To some extent we understand the reason for the similarities in that sterols must “fit” into the phospholipid leaflet which comprises the monolayer component of the common bilayer arrangement of natural membranes1. On the other hand, the reason or reasons for the differences in structure are still elusive. Although we are making a beginning, we still do not yet know why it is that, for instance, people have cholesterol as their major sterol1, while in flowering poinsettia plants only about half the sterol is cholesterol2, in cottonseed oil 93% of the sterol is 24α-ethylcholesterol (sitosterol)1, and in the vine, Clerodendrum splendens, nearly all of the sterol is the 22, 25 (27)-bisdehydro derivative of the 24β-epimer of sitosterol, viz., 25 (27)-dehydroporiferasterol3.
KeywordsPlant Sterol Free Sterol Sterol Structure Exogenous Sterol Membranous Subcellular Fraction
Unable to display preview. Download preview PDF.
- 1.W. R. Nes and M. L. McKean, “Biochemistry of Steroids and Other Isopentenoids,” University Park Press, Baltimore (1977).Google Scholar
- 2.B. C. Sekula and W. R. Nes, The identification of cholesterol and other steroids in E. pulcherrima, Phyto chemistry 19: 1509 (1980).Google Scholar
- 4.W. R. Nes, Biochemistry of plant sterols, in: “Advances in Lipid Research, Volume 15,” Academic Press, New York (1977).Google Scholar
- 12.J. M. Joseph, Influence of side chain structure on metabolism of sterols in Tetrahymena pyriformis, Ph.D. Dissertation, Drexel University (1980).Google Scholar
- 18.W. R. Nes, J. M. Joseph, and J. H. Adler, A comparison of the absorption of sterols with their ability to promote growth in Saccharomyces cerevisiae, Fed. Proc. 40: 1561 (1981).Google Scholar
- 22.C. E. Dahl, H. P. Biemann, and J. S. Dahl, Stimulation of cell proliferation and polyphosphoinositide turnover in a yeast sterol auxotroph by ergosterol, Fed. Proc. 45: 1886 (1986).Google Scholar
- 23.W. D. Nes, R. C. Heupel, and P. H. Le, A comparison of sterol biosynthesis in fungi and tracheophytes and its phylogenetic and functional implications in: “Structure, Function and Metabolism of Plant Lipids,” P. A. Siegenthaler and W. Eichenberger, eds., Elsevier Science Publishers, Amsterdam (1984).Google Scholar
- 24.W. D. Nes, Biosynthesis and requirement for sterols in growth and reproduction of oomycetes, in: “Ecology of Lipids,” G. Fuller and W. D. Nes, eds., ACS Monograph Series, in press (1986).Google Scholar