Vol. April
93, No.
BIOCHEMICAL
3, 1980
AND
BIOPHYSICAL
RESEARCH
COMMUNICATIONS
Pages 967-973
14, 19BO
EXCITATION OF INDOLE ACETATEIN MYELOPEROXIDASEH202 SYSTEM:POSSIBLE FORMATIONOF INDOLE ACETATE CATION RADICAL SHOHEI
KOBAYASHI,
KATSUAKI
SUGIOKA,
AND MINORU NAKANO"
COLLEGE OF MEDICAL CARE AND TECHNOLOGY, MAEBASHI, CHOICHI
TAKYU,
GUNMA, JAPAN
AKIO YAMAGISHI,
RESEARCH INSTITUTE
December
19,
AND HUMIO
OF ELECTRICAL
TOHOKU UNIVERSITY, Received
GUNMA UNIVERSITY
INABA
COMMUNICATION
SENDAI,
JAPAN
1979
Summary: Myeloperoxidase-H2?$ -indole acetate system at pH 7.4 emitted light in visible regi n. Luminescent spectrum showed a weak peak at or near 480 nm and prominent peaks at or near 550, 580, and 620 nm with deep troughs near 500 and 600 nm. In some no definite peak emissions near 550 and 580 nm, but a cases, prominent broad emission between 550 and 580 nm, is observed. Such spectral patterns in the region of 510 to 620 nm were quite similar to those report for the luminescence of photo-products formed firom the indole analogs (tryptophan and indole) in 50 % (365 nm) at 77'K, assuming red shift alcohol irradiated by ii.V. (20-25 nm) by solvent effect. Possible formation of indole acetate cationradical (a precursor of excited indole acetate) was discussed. In excited
linoleate-lipoxygenase in
structures
triplet
states
probably
andan
excited
finding
that
genase
.system
(Type
by the
carbonyl
is
produced
quite
various
without transfer This
(1). spectrum
similar in
* To whom correspondence
I)
energy
chemiluminescent
IAA phosphorescence
Abbreviations:
system,
EPA at
to 77'K,
should
MPO, myeloperoxidase HRP, horse radish
in
between
indole
supported
are
their ring from
the
IAA-linoleate-lipoxy-
reported
assuming
analogs
changes
is
from
that
indole
for red
photoexcited
shift
(35
nm)
be addressed. ; IAA, peroxidase.
indole-3-acetic
acid;
0006-291X/80/070967-07$01.00/0 967
Copyright 0 1980 by Academic Press, Inc. All rights of reproduction in any form reserved.
Vol.
93, No.
via is
3, 1980
BIOCHEMICAL
a solvent also
produced
However, species
effect.
this
from emits
from
in
activated
IAA-MPO-H202 light
The present
in
the
leukocytes
their
the
IAA
the
region
conditions
in
the
work
nm is
probably
involved
which
may be produced
may prove region
reports in from
RESEARCH
IAA
phagocytosing
contain
system
BIOPHYSICAL
an excited
accompanies
emits
morphonuclear under
Such
system
which
AND
of that
in
the
550 to
other
620 nm.
and produce
(3),
spectroscopy
state
system
of
irIP
the
triplet
leukocyte
production
of
COMMUNICATIONS
(2).
excited
Since
poly-
1120,‘ and 02-' of the light
excited
species
which
550 to 620 nm. light
in
the
an additional
triplet
indole
acid
acetic
region state
cation
510-620 (Type
II),
radical.
Materials and Methods Enzyme preparations; Purified glucose oxidase was purchased from Boehringer Mannheim. One unit of the activity was defined as the amount of enzyme which consumed 0.1 nrnole of oxygen/set/ml of The reaction mixture contained 9.3 mM glucose, reaction mixture. 0.06 M sodium phosphate buffer (pH 7.0) and glucose oxidase in a total volume of 3 ml. Oxygen consumption was measured at 25'C in a Yanagimoto oxygenometer Model PO-100A. MPO was prepared from human polymorphonuclear leukocytes according to the methods The peroxidase activity was described by Zyliczydski et al(&). measured by the increase of optical dencity at 485 nm in the presence of p-phenylenediamine and H 02 (5). One unit of the activity was defined as the amount o ? enzyme which caused an absorbance increase of O.OOl/sec/3.2 ml of reaction mixture at 25°C. Specific activity, activity/mg protein, was 200. Protein was determined by phenol-biuret method (6). Incubation; Standard incubation mixture contained 9.3 mN glucose, 5.59 units of glucose oxidase, 85 units of PIPO, 200 UN IAA, and 0.06 M buffer (acetate buffer for the pH lower than 6.0 or phosphate buffer for the pH between 6.0 and 7.4) in a total volume of 3.0 ml. The reaction was initiated bv the addition of glucose . In some cases, 1.1 mM H202 was added ;o a incubation mixture excluding H.2 0 2 generating system (glucose-glucose oxidase) from th e standard incubation mixture. Incubation was conducted at 25'C without shaking (except for the initiation of the reaction). Cherniluminescent measurements; Luminescent intensity (counts/ min) was measured by Luminescence Reader, Aloka BLK-101 at 25'C. Background count was approximately 35-50 counts/min. This counter is convenient for continuous detection of luminescence, i.e. counts/3 set can be calculated to be counts/min which were recorded on the papre durin,g incubation. even thou,zh the photomultiplyerequipped‘has low sensitivity compared with that 0T ordinary scintillation counter. Chcmi iuminfscent spc ctra were taken by our spectrometer (7).
968
Vol.
93, No.
3. 1980
BIOCHEMICAL
AND
BIOPHYSICAL
RESEARCH
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Qualitative analysis of products; The reaction mixture was extracted 3 times with equivolume of ethylacetate containing 50 PM 2,5-di-t-butylhydroquinone, the pooled extract was dried over Na2S04 and the organic solvent was removed under reduced pressure. The residue was dissolved in methanol. An aliquot of the methanol solution was then analyzed by thin layer chromatography (I) and high pressure liquid chromatography, using authentic samples as markers. The assay conditions for the latter were followes; equipment, Hitachi Model 633A; column, 3010 methanol-water (17:3 V/V); pressure, solvent, (1 m>; e.)uting 30 kg/cm'-.
Results
,and Discussion When 1.1
excluding
H202
mixture,
pH and
decreased
The
standard present. emitting
rapidly
the
from
after of
reaction Some of
mixture these
standard
detected
in
was which
results
are
luminescence,
(pH incubation
region
pH up to near maximum,
greatly H202
5.0)
by a photon
visible
increasing its
mixture
appeard
at
pH 7.4,
but
probably
to O2 by a catalase-like
reaction
the
in
reaching H202
the
was
luminescence with
luminescent
species,
system
increased
decomposition
(8).
to a reaction
or no luminescence
However,
higher
added
generating
little
counter.
the
mM H202 was
because
action
prolonged generating
shown
in
Fig.
which
appeared
in system 1. after
of
of MPO the is
To know the
the peak
intensities in the MPO-H 0 -1AA systems Fig. 1.- Chemiluminescent __The reaction was initr .2 t ii d by the as a function of the time. addition of H20a for a system excluding H 0 generating system The or of glucose f r the standard incubation 21m xture (arrow). incubation was conducted at pH 7.4 and at 25'C.
969
Vol.
93, No.
BIOCHEMICAL
3, 1980
AND
3 I,
1
3
1
4
nmxl0 ’
BIOPHYSICAL
F25
’
RESEARCH
COMMUNICATIONS
6
’
t
’
’
54oY35mfm620~
hm)
WAVELENGTH
Fig. 2. Chemiluminescent spectra and or the photoproduct of indole at 77'K (after Vladimirov et al.). emission for
and decaied
our spectral
gradually
near
480 nm and prominent
with
deep troughs
no definite prominent
Such spectral
500 and 600 nm (Fig.
2).
at or near between
in the
reported
for
580 and 620 nm In
550 and 580 nm was observed.
region the
of
510 to 620 nm are quite
to those
formed
from indole
analogs
(tryptophan
and indole)
ethanol
irradiated
by U.V.
(365 nm) at
77OK (9),
shift (20-25 nm) by solvent effect. 1 OE 02 in aqueous system also emits 520,
nm.
The weak luminescence
580,
and 635 nm (7),
some cases,
550 and 580 nm, but a
similar
i.e.
was subjected
showed a weak peak at or 550,
emission
patterns
fashion,
peaks at or near
peak emission broad
in a linear The spectra
analysis.
near
of MPO-H 0 -1AA (la and lb) (2) or Ih2(3) in 50 % ethanol
but
luminescence
Binary
does not
in 50 % assuming
collision
in the region
at or near
970
of photoproducts
emit
of
red lA
g type 500 to 640 nm;
at or near
480 nm in MPO-H202-IAA
550 is
Vol.
93, No.
3, 1980
BIOCHEMICAL
AND
BIOPHYSICAL
e
RESEARCH
COMMUNICATIONS
e
(IAd)
lAA*
-
IAA
+
Figure
considered
ponding
laboratory to 'A
l-3
(l),
the present
system
cation
(Fig.
radical
NH group
in indole
complex.. like
solvated
of 4.2
for
radical.
not iron
could
the
clarified
Electron
(10).
excitation
at neutral
at the
present
As shown in Fig.
4,
source
hand,
electron
to
higher
pH is
or of anion
shown in Fig. nature
the indole
of
from pKa
radical
3, could
of
rings
pH has been reported
the
present,
cation
a specific
from
such a radical
electron
of IAA,
with
pH, judging
On the other
solvated
cation,
to react
at neutral
from
of MPO-H202
radical
However,
of
anion
of electron
a while
of tryptophan
transfer
or a radical
analogs
radical.
of
Even though
of MPO in the
1 hr-incubation
for
or in enzyme with
coenzymes (11).
indole
be remained
stability
(9)
be caused by the action of
in
in the reaction
abstraction
system,
radical
However,
environment.
Giusti
electron
solvated
be deprotonated
the
in protein
corres-
510 to 630 nm observed
with
or an anion
neutral for
has been reported
be a fluorescence
to be involved
the deprotonation
tryptophan
pyridine
of
ring
electron (can easily
occur
in the region
which
is considered
should
cation
suitable
not
For the excitation
IAA.H+',
IAA,
but would
In IAA-MPO-H202
3).
of
+
The luminescence
IAA
3
to be a phosphorescence
from our
hv
local
to
the
by Cilento
such reducing may be supplied
agents
and is
from heme-
system. the metabolites
were indole-3-carboxylic
971
obtained acid,
from IAA during
indole-3-aldehyde,
Vol.
93, No.
BIOCHEMICAL
3, 1980
AND
BIOPHYSICAL
RESEARCH
COMMUNICATIONS
pattern of the compounds with absorption Fig. 4. Chromatographic at 254 nm (A254) in the standard incubation mixture (pH 7.4) ICA, indole-3-carboxylic acid; IA, indole-3incubated for 1 hr. SK, skatole; XI-X3, unknown aldehyde; MOI, methyleneoxyindole; compounds.
methyleneoxyindole,
and unidentified
skatole,
o-formylaminoacetophenone (lo2
derived
product)
chromatography
and
same metabolites in
which
at
Therefore
the
could
detected
system
by the
thin
layer
also
be formed with
main
peak
unlikely
that
attended
by a structual-
though is
certain
unknown,
on IAA occurs
be observeu
in
seems is
in
is the
of dark
high
pressure
of
II"
at
or
biological
liquid The
system
(pH
that
data).
of
in MPOIAA.
in MPO-H202-
a mimic system.
7.4),
410 nm and
luminescence change
acid
(1).
near
luminescence
interest
972
IAA-HRP
(unpublished
"Type
mechanism it
acetic
chromatography
could
system
Even
o-formylaminobenzoyl
480 nm
it
H202-IAA
action
was
chemiluminescence
shoulder
IAA
nor
Neither
compounds.
photodynamic
Vol.
93, No.
3, 1980
BIOCHEMICAL
AND
BIOPHYSICAL
RESEARCH
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References 1) Nakano, M., and Sugioka, K. (1978) Biochem. Biophys. Acta 529, 387-397. 2) Ushijima, Y., Nakano, M., Tsuji, Y., and Inaba, H. (1978) Biochem. Biophys. Res. Commun. 82, 853-858. 3) Babior, B.N., Kipnes, R.S., and Gurnutte, J.T. (1973) J. Clin. Invest. 52, 741-744. 4) Zaliczynski, J.M., Stelmasxynska, T., Ostrowski, Id., Naskalski, J and Sxnajd, J. (1968) Eur. J. Biochem. 4, 540-547. 5) Luik, I-I. (1963) Methods of Enzymatic Analysis (Bergmeyer, H.U. ed.) pp. 895-897, Academic Press, New York and London. 6) Lowry, O.H., Rosebrough, N.J., Fsrr, A.L., and Raudall, R.J. (1951) J. Biol. Chem. 193, 265-275. 7) Nakano, M., Noguchi, T., Sugioka, K., Fukuyama, H., Sato, M., Shimizu, Y., Tsuji, Y., and Inaba, H. (1975) J. Biol. Chem. 250, 2404-2406. 8) Paul, K.G. (1963) 'The Enzymes (Boyer, P.D., Larday, H., and Myrback, K. eds.) and ed. vol. 8, pp. 227-274, Academic Press, New York. 9) Vladimirov, Yu. A., Roshchupkin, D.I., and Fesenko, E.E. (1970) Photochem. Photobiol. 11, 227-246. 10) Adams, G.E., and Wardman, P. (1977) Free Radicals in Biology (Pryor, W.A. ed.) vol III, pp53-95, Academic Press, New York. 11) Cilento, G., and Giusti, I-'. (1959) J. Am. Chem. Sot. 81, 380-l-3802.
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