The metabolic role of the 24-ethylidenecholesterols

BIOCHEMICAL

Vol. 31, No. 4, 1968

THE METABOLIC R.T.

ROLE OF THE 24-ETHYLIDENECHOLESTEROLS*

van Aller,

H. Chikamatsu,

J.P. Department

of Chemistry,

tain

epimeric

species

Kishida which

they

(1963);

arise

Bader,

and Lederer

Knights

Lederer

(1964))

to a 24-methylenesterol.

already

that

fucosterol

of two methyl

(1964, Blondin

1965);

groups

Mercer

and Nes (in

lar

to the known

Steinberg

Goad,

by reduction reduction

of the

(1960);

Avigan

should

the

We would

compounds. and

(Castle, (1964);

Barbier

Q-sitosterol

to report

from Pinus

generally here

pinea,

the

group

algae the

it

is

addi-

and Lederer (1966);

however

Hickey (1961)).

Barbier,

with

nucleotide

and Steinberg quite

Audier,

and Goodwin

(Stokes,

Birch

of brown

(Villanueva,

could

in

of the methyl

mevalonate

A 24 -bond

like

Vetter,

via

pyridine

Hayatsu,

The manner

species

Hammam, Dennis

be present

Tsuda,

the addition

arise

from cer-

and Nes (1963);

HGgel,

In various

with

(1934);

Blondin

to involve

isolated

(1967)).

24-Ethylidenesterols

the 24-ethylidenesterols

29-isofucosterol

Baisted

does indeed

press)).

and Avigan

24-ethyl

(1965);

from methionine

(1965);

to the 24-ethylsterols

have been and Wright

and Arigoni

of methionine

tion

38677

Phipers

has been postulated Guglielmetti

de Souza,

of Mississippi,

Mississippi

(Heilbron,

(1958);

(1964);

known

University

24-ethylidenecholesterols

of plants

and Akagi

N.J.

John and W.R. Nes

University,

Several

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

Castle,

also

give

in a manner and Fish If

this

in plants isolation

the biosynthesis

rise simi-

(1958); were

true,

which

form

of both of

*Inquiries regarding this paper should be addressed to Prof. W. R. Nes, Sciences, Drexel Institute of Technology, Philadelphia, Dept. of Biological Pa. 19104. The support of grant No. 5ROl-AM09100 from the National Institutes of Health is gratefully acknowledged.

842

BIOCHEMICAL

Vol. 31, No. 4, 1968

29-isofucosterol

from mevalonate

lenecholesterol,

and its

reduction.

The data

conversion

obtained

to 24-ethylidene also

Castle,

are

Blondin

(which

a category

with

a genetic

block

*24(28)

_ and

the yeasts

A7-bonds

Gas-liquid

(which

cholesterol.

m.p.

127-130°,

distinguishes acetate,

tical

with

faster

Incubation

thin

than

a radioactive layer

synthetic

from

of silica

gel

on a thin

alcohol

29-isomer (lacking

Authentic

The ketone of silica

yielded

29-isofucosterol

identified

by AgN03 -thin

843

acetate 6.0 mg. from 12.25

(1960)),

coat)

with

movements (from

latter

and g. l.c.

layer

idenmoved

procedures.

of the acetate without

(126.5-127.5’))

20) with

(as the

(as

Fucus)

acetate

Similar

Tween

which

on a AgNC3-

sample

by m.p.

350

2-C 14 -mevalonate

as the acetate

24-ketocholesterol

P layer

thin

XE-60)

an authentic

(in

28-C14 -24-methylenecholesterol

impregnated

Amax

the

was identified gel,

8 -sitosterol.

sterol,

in both outer

as did

with

fucosterol

chromatographing

precisely

137-140°,

29-isofucosterol

(silanized,

their

by the usual

m.p.

nitrate

(Dusza

(synthetic)

the

30% of 24-methyl-

129-131°,

fucosterol

and g.1.c.

Ozonization

layer

on silver

8% of total

the free

substance

of radioactivity.

movement

of

of the seeds

of 29-isofucosterol. loss

contained

have

sterol.

plates,

mixture

to be in

of which

was obtained

also

the sample

appear

investigated,

identical

29-isofucosterol. its

there

to 24-methyl alternatives).

both

spectra

sterol

for

thus

and n.m.r.

AgN03-impregnated) synthetic

(1967)

in the dominant pinea

constituent,

29-isofucosterol

the

slightly

m.p.

24-methylene

organisms

chromatography

minor

AZ4 to 24-methylene

colorless

acetylated

as a very

the pathway:

procedures

showed layer

reduced

of Pinus

infrared

of the crude

was isolated

yielded

seeds

From thin

gel

seeds,

found

by

to 24-methylcholes-

A 5,7 -sterol)

In most

24-methy-

was converted

and Lederer

accrrmulate

from

presumably

the conversion:

step.

are

chromatography

formation

the 24-ethylidenesterol)

at a reductive

(CRC13),

with

and with

and chromatographic

-33.2’

silica

consistent

accumulate

its

to 24-ethylcholesterol

and Nes (1963)

From the ungerminated extraction

species,

similarly

to 24-ethyl

Fucus species

Wp

in this

24-Methylenecholesterol

terol.

(see

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

incubation the

acetate)

seeds

I.R., of yielded

and gas-liquid

BIOCHEMICAL

Vol. 31, No. 4, 1968

Refncubatfon

chromatography. gave

e-sitosterol

recovered

as unchanged

failed

By contrast,

labelled

highly

substance

(Russell,

van Aller

methylenecholesterol terol

was obtained,

saturated

portion

The labelled as did

to undergo

and Nes (in

identified

as is

press)).

From

layer

osmium

converted

to

tetroxide.

24-methylenecholesterol

incubation

of 28-C 14-24-

labelled

24-methylcholes-

to 29-isofucosterol

of the AgN03-thin

and when

to a chromatographically

labelled the

being

chromatographed

with

was converted

by gas-liquid

radioactivity

sample

a reaction

technique

in addition

29-isofucosterol

k-sitosterol

an authentic

29-isofucosterol by this

and purified

most of the remaining

substrate.

on AgNO -TLC) 3

3,5-cycloderivative

polar

the labelled

in 3.6% yield,

(as the acetate the

of

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

chromatography

of the side

chain

chromatogram.

References J. Avi.gan and D. Steinberg (1961)) J. Biol. Chem., 236, 2898. S. Bsder, L. Guglielmetti and D. Arigoni, (19641, Proc. Chem. Sot. (London), 16. D. J. Bafsted (1967)) private communication. A.J. Birch (1963). in T. Swain, editor, Chemical Plant Taxonomy, Academic Press, 162. M. Castle, G. Blondin and W.R. Nes (1963), J. Am, Chem. Sot., 85, 3306. M. Castle, G. Blondin and W.R. Nes (in press), J, Biol. Chem. J.P. Dusza (1960)) J. Org. Chem. , 25, 93. L.J. Goad, A.S.A. Hammam, A. Dennirand T.W. Goodwin (1966), Nature, 210, 1322. I. Heilbron, R.F. Phipers and H.R. Wright (1934)) J. Chem. Sot., 1572. M.F. H$el, N. Vetter, H. Audier, M. Barbier and E. Lederer (1964), Phytochem., 2, 7. B.A. Knights (1965)) Phytochem., 4, 857. E. Lederer (1964), Biochem. J., 93, 449. E. Lederer (1967)) Tetrahedron Letters, 12, 1049. E.J. Mercer (1965)) Bfochem. J. 2, 17P. P.T. Russell, R.T. van Aller and W.R. Nes (in press), J. Biol. Chem, D. Steinberg and J. Avigan (1960), J. Biol. Chem., 235, 3127. W.M. Stokes, F.C. Hickey and W.A. Fish (1958), J. Bm. Chem., 232, 347. K. Tsuda, R. Hayatsu, Y. Kishida and S. Akagi (1958), J. Am. Chem. Sot., 80, 921. V.R. Villanueva, M. Barbier and E. Lederer (1964), Bull. Sot. Chim. France, 1423. V.R. Villanueva, M. Barbier and E. Lederer (1965), Beitr. Biochem. Physiol. Naturstoffen Festschr., 509.

844