Function of steryl esters in plants: A hypothesis that liquid crystalline properties of some steryl esters may be significant in plant sterol metabolism
| Autor: | A. M. Atallah, Harold J. Nicholas |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Hot Temperature
Time Factors Double bond Molecular Conformation Palmitates Palmitic Acids Tritium Biochemistry Thermotropic crystal Palmitic acid Hydrolysis chemistry.chemical_compound Liquid crystal Ergosterol Plant Cells Organic chemistry chemistry.chemical_classification Cell-Free System Organic Chemistry Mesophase Esters Cell Biology Plants Sitosterols Mitochondria Sterols Cholesterol chemistry Chromatography Thin Layer Crystallization Mitochondrial Swelling |
| Zdroj: | Lipids. 9:613-622 |
| ISSN: | 1558-9307 0024-4201 |
| DOI: | 10.1007/bf02532510 |
| Popis: | The synthesis of a wide variety of desmethyl, 4α- and 4,4-dimethyl steryl esters, whose physical properties have been described elsewhere, has indicated that side chain structure and the position of a double bond in the nucleus are critical in determining whether or not a steryl ester can form a mesophase (liquid crystalline state). Since the capability of mesophase formation seems rather specifically distributed in the biosynthetic steps leading to the formation of animal, plant, and fungal sterols, the hypothesis is presented that such mesophase formation, or lack of it, may control the biosynthetic sequence by virtue of the viscosity changes associated with the formation of liquid crystals. Mesophase formation of thermotropic liquid crystals is influenced by a number of physical factors, including heat, electrical current, pressure, and impurities, e.g. solvents. Some preliminary experiments with incubation of cell-free extracts ofPhaseolus vulgaris are reported, with heat as the physical parameter studied, following the addition of cholesteryl-1,2-3H, sitosteryl-22,23-3H(N) palmitates, and the respective free compounds to the cell-free extracts. Although some possible influence of heat during the incubation of the compounds upon their distribution in subcellular fractions was indicated, no consistent pattern was found. However, some observations on the capability of the subcellular organelles to hydrolyze the added esters and esterify the free compounds are presented. The data suggest that hydrolysis of steryl esters and their synthesis by plant cell-free extracts are both of more than coincidental occurrence. |
| Databáze: | OpenAIRE |
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