Incorporation of 2-C14-mevalonic acid into tomato carotenes

Vol. 1, No. 2

BIOCHEMICAL

OF 2-C14 -MEVALONIC

INCOHPOHATION

David G. Anderson,

ACID INTO

David W. Norgard

The Radioisotope

Unit,

Veterans

tomatoes

rapidly

Administration

with phytoene,

incorporate

phytofluene,

Separation

by rechromatography p-carotene crystallization tography

on a different

developing droxide.

radioactivity.

from radioactive

Ethyl ether-petroleum

these columns.

freed of high counting

Neurosporene,

contaminants

The spectral

14

purity

5 -carotene,

radioactivity

adsorbent

specific

are separated

on alumina.

2-C

Y -carotene,

in the case of each of these comradioactivity is not present in the

are freed of radioactive

to constant

and 5 -carotene

injected

of the contaminating

and lycopene

Hospital,

Chemistry Wisconsin

p -carotene,

neurosporene and lycopene. However, pounds at least 9% of the accompanying carotenoid.

CAROTENES*

-mevalonic acid Chromatography on MgO - Super Cel columns of these compounds shows an association of

into non-saponifiable lipids. of a petroleum ether extract carbon-14

TOMATO

and John W: Porter

and the Department of Physiological University of Wisconsin, Madison, Ripening

Aug. 1959

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

may be achieved

or by crystallization.

Thus

contaminants

through

Phytoene,

phytofluene

impurities

through

ether mixtures

chroma-

are used in

Y -carotene

and lycopene

are

by rechromatography

on calcium

hy-

carotenes

and

of the eluted or crystallized

colorless polyenes was demonstrated with a Process and Instruments recording spectrophotometer. In the case of the eluted carotenoids, specific radioactivity

measurements

for each compound. activities

April A-1383,

were made upon the series

Those fractions

were combined

and further

of similar

of eluates

or identical

proof of the presence

collected

specific

radio-

of Cl4 in each

* Presented in part at the Boston Meeting, American Chemical Society, 1959. This investigation was supported in part by a research grant, from the National

the National

Institutes

Institute

of Health,

of Arthritic United

83

and Metabolic

States Public

Health

Diseases Service.

of

Vol. 1, No. 2

BIOCHEMICAL

of these compounds Crystalline,

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

was obtained

non-radioactive

less polyene,

i.e.

lycopene.

lycopene

phytoene,

and the compound

activity.

complete

Coincidence

catalytic

5 -carotene

hydrogenated

compound

was also obtained

carotenoids

is further

(Rabourn

and Quackenbush,

appeared

in the adduct.

lycopene

and 60% or more of the radioactivity

appeared

in perhydrolycopene.

product

of the thiourea

1956).

adduct of

All of the radioactivity

In all cases at least 9% or more of the carrier

was taken as the measure

carotenoid.

on alumina.

of reduced 14 of C in these

The presence

by the formation

perhydro-

between weight and radio-

between radioactivity

and weight of perhydrolycopene.

or color-

and neurosporene,

to the derivative

was obtained

y -carotene

perhydrolycopene

of each.

was then chromatographed

coincidence

evidenced

hydrogenation

was added to each carotene

phytofluene,

was catalytically

The hydrogenated

In each instance

through

Aug. 1959

of the purified

carotenoid

The radioactivity

present

in the hydrogenated

of radioactivity

present

in the original

These values were used in calculating

the specific

radioactiv-

ities given in Table I. The values clearly

indicate

that 2-C 14 -mevalonic

into each of the carotenoid

compounds

listed,

into other non-saponifiable

compounds

synthesized

of Table I are at variance,

where comparisons

Purcell,

Thompson

acid is incorporated

but much less effectively by the tomato.

can be made,

than

The data

with those of

and Bonner

(1959) who did not present

convincing

dence of a high degree of purity

of most of the carotenoids

which they sepa-

rated.

a4

evi-

Vol. 1, No. 2

BIOCHEMICAL

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

Aug. 1959

Table I SPECIFIC

RABIOACTIVITIFS Total

Compound

P hytoene

OF TOMATO

CAROTENOIDS

radioactivitya

First c hromatogram

Second chromatogram

After reduction

Specific radioac tivitv

c/mm.

c/min.

c/min. 1238

c/m/q5 2870,200

1142 310 45

3080*200 750*100

224

3450f250

2,060, OOOb

P hytof luene 5 -carotene

459, ooob 24, 300b

Neurosporene

20, 5oob

Y -carotene

37, ooob

1295 1995c 440b 2a4b

Before crystallization

780+150

After crystallization

Lycopene

162, OOOb

la, 400~

P -carotene

242, OOOb

7, a50b

3110*

5ob

6400*100b

a Radioactivity was measured with a Packard Tri-Carb liquid scintillation spectrometer. b Radioactivity was measured with a thin end window gas-flow GeigerMuller tube, and values were corrected for comparison with those obtained with the liquid scintillation spectrometer. ’ Radioactivity

values were corrected

for quenching.

REFERENCES Purcell, A. E., Thompson, 234. 1081 (1959). Rabourn,

G. A.,

W. S. , and Quackenbush,

Jr.,

F. W.,

111, (1956).

Received

and Banner,

August 6, 1959

85

Arch.

J.,

Biochem.

J. Biol.

Chem.,

Biophys.,

61,