Эргостирол

Описание

Ergosterol is a membrane component and with few exceptions is restricted to eumycotic fungi (101). As a constituent of intact membranes, its abundance should reflect the amount of living fungal biomass in an environment. This membrane component has been related to biomass by a number of investigators and the values range from 1.9 to 11.5 mg ergosterol g?1 mycelium (102). These conversion factors yield very high values for fungal biomass, and seem unrealistic (102) when compared with independent measures of bacterial biomass. It is likely that the ergosterol assay detects nonliving hyphae and these measures may overestimate viable fungal biomass. Similarly, chitin is a dominant cell wall component in most fungi and has been proposed as a unique marker for total fungal biomass.

Химические свойства

solid

Использование

Ergosterol is a steroid alcohol that when irradiated with ultraviolet light yields calciferol (vitamin d2). irradiated ergosterol is added to milk for vitamin d fortification.

Определение

ergosterol: A sterol occurring infungi, bacteria, algae, and plants. It isconverted into vitamin D₂ by the actionof ultraviolet light.

Общее описание

Ergosterol or provitamin D2 is a biological precursor of Vitamin D2. It is found predominantly in cell membranes of fungi and protists such as trypanosomes.

Опасность

Due to its ability to catalyze calcium deposition in the bony structure (thus preventing rickets), overdosage of vitamin D may be harmful.

Методы очистки

Crystallise ergosterol from EtOAc, then from ethylene dichloride or EtOH/*C6H6 (3:1). It has been purified by conversion to the isobutyl ester which crystallises from Et2O/Me2CO (1:3) with m: turbid at 148o, melts at 159o and becomes clear at 162o, followed by hydrolysis, [Bill & Honeywell J Biol Chem 80 15 1938]. When crystallised from EtOH, it forms the 1.5-hydrate m 168o. The water is difficult to remove giving an amorphous solid m 166-183o, b 250o/high vacuum. It is light sensitive. The benzoate has m 169-171o, after crystallisation from Me2CO/*C6H6 (4:1) after prolonged standing at 0o and becomes highly charged, with [] D20 -177o (c 1, CHCl3). [UV of sterols: Hogness et al. J Biol Chem 120 239 1937, Beilstein 6 IV 4407.]