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.
화학적 성질
solid
용도
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.
정의
ergosterol: A sterol occurring infungi, bacteria, algae, and plants. It isconverted into vitamin D2 by the actionof ultraviolet light.
일반 설명
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.
위험도
Due to its ability to catalyze calcium deposition in the bony structure (thus preventing rickets),
overdosage of vitamin D may be harmful.
Purification Methods
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.]