Increased activity of tryptophan peroxidase in HeLa cells

Vol. 6, No. 3, 1961

BIOCHEMICAL

INCREASED ACTIVITY

AND BIOPHYSICAL RESEARCH COMMUNKATiONS

OF TRYPTOPHAN PEROXIDASE IN HeLa CELLS

C. Paul Kenny and Howard Lees Department

of Microbiology, Winnipeg,

University Canada

of Manitoba

Received October 11, 1961 Substrate

(1960,

Klein in vitro,

induction

1961)

to occur

presumably

bacteria

and other

Y rotatory

enrichment

bath

of the air

medium used consisted #19g1 to which over

a year.

were able successive

this

inherently "induced

out

cultured

generations

Air

CO2 was found

of 20s calf strain

suspension

gas phase;

to be unnecessary.

serum and 80% Morgan's

of HeLa cells

on a

Mixture

has been adapted

suspensions

The

for

were monodisperse,

methods exclusively

to obtain

of cells. suspensions

enzyme synthesis"

1 From Microbiological

in

on an established

was used as the

seemed to offer

more homogeneous and tractable

their

as monolayers

operates

study

in monodisperse

shaker. with

a parallel

to use bacteriological

We have tested

cultured

same mechanism that

Because the cell

Monodisperse

cells

by

microorganisms.

of HeLa cells water

in animal

by the

We have now carried strain

of enzymes has been demonstrated

than

did cells

suitability

for

Associates, 224

for

material the

study

of

grown as monolayers.

such a study:by

Bethesda,

Md.

following

we

Vol. 6, No. 3,196l

the

BIOCHEMICAL

"induction"

suspensions

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

of tryptophan under various

a similar

of TPO synthesis

Raising

the medium from 10 -4 E to measureable

increase

(TPO) in such cell

conditions.

There was no evidence in the medium alone.

peroxidase

the L-tryptophan

10-2 g did not

of TPO activity.

difficulty

with

the

The addition

of RNA was made on the basis

tried

of cells

RNA (Sigma Chemical tryptophan of the

Co.),

concentration

"RNA" cultures

The cultures according

encountered but was

RNA to the culture

the

effect

medium.

of an hypothesis

of

in basal

of cells

in basal

medium plus

250 kg/ml

were grown for in five

24 hours.

of the

was then

were then

of RNA and L-tryptophan

Ten cultures

and together,

and ten cultures

(1961)

(1955).

We therefore separately

adding

of

to a

of arginase

successful

et al.

after

rise

Klein

induction

cultured

concentration

give

subsequently

Speigelman

in cells

raised

assayed

"basal"

yeast

The L-

cultures

and five

from 10N4 g to 10B2 M.

from time

to a method essentially

medium,

the

to time

for

same as that

the enzyme used by Knox

(1955) No activity containing TPO activity

extra

was observed RNA and extra

increased

was measured by the amount of L-kynurenine homogenate

with

in any culture tryptophan.

as culture

L-tryptophan

during (Knox,

225

In these

determination the aerobic

those cultures,

The activity

age increased.

spectrophotometric formed

except

of the

incubation

1955) at 365 mp,.

of

Vol. 6, No. 3‘1961

BIOCHEMICAL

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

Age of Culture

Activity

(Knox

0 says

0.00

4 days

1.62

8 days

2.62

9 days

3.00 3.41

10 days

The monodisperse for

the

study

of

81induced

We are currently phenomenon

is

activation

of TPO protein

curious

effect

units)

suspensions enzyme

are thus

to determine induction

already

of RNA on the

suitable

synthesis".

attempting

due to substrate

perfectly

is

this

of TPO synthesis

present

system

whether

in also

the being

cells.

or to The

investigated.

REFERENCES Klein, E., Etipt'l Cell Res. 21, 421 (1960). Cell Res. 22, 226 (1961), Klein, E., Expt'l Knox, w. E., J. Biol. Chem. 214, 307 (1955). Speigelman, S., Halvorsen, H. O., and Ben-Ishai, R., Amino Acid Metabolism, page 124, McElroy, W. D. and Glass, B. (eds.) Johns Hopkins Press, Baltimore (1955).

226