Photoregulating catalytic activity of cyclodextrin-based artificial glutathione peroxidase by charged azobenzene

Article abstract of DOI:10.1007/s10562-010-0363-7

Modulating the activities of enzymes by using an external signal is widely used for many applications. In this paper, it has been performed for the first time that photoregulating the activity of artificial glutathione peroxidase (GPx) by using photocontrolled inclusion-exclusion reaction of the azobenzene with two typical GPx mimics, the telluride β-Cyclodextrin (β-CD) dimmer and the ditelluride β-CD dimmer. The activities of both mimics were differently inhibited by either cationic or anionic azobenzene, owing to the catalytic capacity variance of the telluride moieties of the mimics and the different strength of the electrostatic interactions between the charges of the substrates and the azobenzenes. The inclusion of the anionic azobenzene with the ditelluride β-CD dimmer represented the largest inhibition rate. When the inclusion was irradiated upon UV light, the activity recovered, whereas inhibited again upon visible light. Such process could be repeated many times and a switchable artificial enzyme based on the reaction was proposed. Graphical Abstract: It was performed that photoregulating artificial enzyme by using photocontroled inclusion-exclusion reaction of one 6-ditellurium β-CD dimmer with two anionic azobenzenes. When inclusion underwent the activity of the artificial enzyme was inhibited. After irradiation with UV light, the cis-isomer azobenzene formed, and went away from the cavity left an appropriate cavity for accommodating a substrate, as a result, the activity recovered. After irradiation with visible light, the activity was inhibited over again, owing to that the trans-isomer azobenzene regenerated, and regressed to the inclusion. Such process could be repeated many times.

Full text of DOI:10.1007/s10562-010-0363-7

Catal Lett (2010) 138:62–67
DOI 10.1007/s10562-010-0363-7
Photoregulating Catalytic Activity of Cyclodextrin-Based
Artificial Glutathione Peroxidase by Charged Azobenzene
Ping Wu
Lipeng Zhou
•
Ruiqing Xiao
Quan Luo
•
Chunqiu Zhang
Jiayun Xu Junqiu Liu
•
•
•
•
Received: 23 March 2010 / Accepted: 26 April 2010 / Published online: 20 May 2010
Ó Springer Science+Business Media, LLC 2010
Abstract Modulating the activities of enzymes by using
an external signal is widely used for many applications. In
this paper, it has been performed for the first time that
photoregulating the activity of artificial glutathione per-
oxidase (GPx) by using photocontrolled inclusion–exclu-
sion reaction of the azobenzene with two typical GPx
mimics, the telluride b-Cyclodextrin (b-CD) dimmer and
the ditelluride b-CD dimmer. The activities of both mimics
were differently inhibited by either cationic or anionic
azobenzene, owing to the catalytic capacity variance of the
telluride moieties of the mimics and the different strength
of the electrostatic interactions between the charges of
the substrates and the azobenzenes. The inclusion of the
anionic azobenzene with the ditelluride b-CD dimmer
represented the largest inhibition rate. When the inclusion
was irradiated upon UV light, the activity recovered,
whereas inhibited again upon visible light. Such process
could be repeated many times and a switchable artificial
enzyme based on the reaction was proposed.
to diverse growth conditions [1]. As one kind of antioxi-
dative enzyme, the selenium-containing glutathione per-
oxidase (GPx) represents a cell-specific and tissue-specific
mechanism for prevention of oxidative damage in mam-
malian systems [2]. To elucidate whether the enzyme has a
more subtle role in regulation of tissue peroxide levels than
a blanket protection against oxidative stress, some methods
and strategies of precise manipulation of the GPx activity
have been developed, such as minimal modifications at
enzyme active sites [3], changing selenium levels in diet
[4], molecular over-expression [5] and knockout [6] tech-
niques. However, they are usually static and unresponsive
to the environmental effects. Because of the convenience,
expeditiousness, and economy, it will be an alternative
method that triggering and control of the enzyme activity
[7] with light absorption of bistable photoswitches [8], for
example, azobenzene and spiropyran derivatives.
Recently in our group, a series of artificial GPxs have
been constructed by monoclonal antibody, bioimprinting,
and transferring nature enzymes techniques etc. Especially,
cyclodextrin-based enzyme models [9–11] have been
designed by cooperating both recognition by cyclodextrin
and catalysis by telluride contained moiety, which are not
only extremely attractive components for both pharma-
ceutical and academic interests [12, 13], but also have great
potential for further constructing promising materials as
well as molecular machines [14, 15]. Since the first
experiment on photoregulation of an enzymic process by
means of light was performed [16] in 1968, photoswitches
have been used in a number of biotechnology applications
[7, 17–19]. However, to our knowledge, there are only
several reports about photocontrolled artificial enzyme on
cyclodextrin-based biomimetic performance in the field
Keywords Photoswitch ꢀ Selenoenzyme ꢀ Reversible ꢀ
Dimer ꢀ Shuttle ꢀ Biomimetic
1
Introduction
A balance between oxidant and antioxidant intracellular
systems is vital for cell function, regulation, and adaptation
JP .. LWi uu (ꢀ&R ). Xiao ꢀ C. Zhang ꢀ L. Zhou ꢀ Q. Luo ꢀ J. Xu ꢀ
State Key Laboratory for Supramolecular Structure
and Materials, College of Chemistry, Jilin University,
130012 Changchun, People’s Republic of China
e-mail: junqiuliu@jlu.edu.cn
[
20–23] and none about photoregulation of selenoenzyme.
In the present study, we have extended our work to the field
1
23

Photoregulating Catalytic Activity of Cyclodextrin-Based Artificial Glutathione Peroxidase
63
of controlling the catalytic process of artificial GPx subject
to photoregulation for the first time. As typical artificial
purified by silica gel column chromatography. A yellow
powder was collected after the evaporation of the solvent.
Synthesis of (2b): [4-(2-Bromo-ethy)-phenyl]-diazene
was dissolved in excessive pyridine. The mixture was kept
stirring for 8 h at 60 °C under Ar protection. After evap-
oration of pyridine, the yellow solid was dissolved in
methanol. The solution was added dropwise with stirring to
plenty of ethyl ether, and the yellow precipitate was filtered
0
GPx mimics, the telluride b-CD dimmer—6,6 -telluro-bis
(
6-deoxy-b-cyclodextrin) (1a) and the ditelluride b-CD
0
dimmer—6,6 -ditelluro-bis (6-deoxy-b-cyclodextrin) (1b),
have been selected and photoregulated by using photo-
controlled inclusion–exclusion reactions of the anionic
azobenzene—4-phenylazophenoxyacetic acid (2a) and the
cationic azobenzene—1-[2-(4-phenylazophenoxy) ethyl]
pyridinium bromide (2b) with them.
1
and dried in vacuum. H NMR (300 MHz, (CD ) SO)
3
2
d = 9.17 (d, 2H), 8.66 (t, 1H), 8.21 (t, 2H), 7.90–7.81 (m,
4H), 7.60–7.52 (m, 3H), 7.13 (d, 2H), 5.10 (t, 2H), 4.65 (t,
2H).
2
Materials and Methods
2.4 Determination of Activity
2
.1 General Materials
The catalytic activity of CD-based GPx was measured
according to the regular method reported by Hilvert et al.
[25] using TNB (3a) and cumene hydroperoxide (CUOOH,
3b) as substrates (see following chemical equation):
0
Compounds 6,6 -telluro-bis (6-deoxy-b-cyclodextrin) (1a),
6
0
,6 -ditelluro-bis (6-deoxy-b-cyclodextrin) (1b) [11], 4-
phenylazo-phenol and 1-[2-(4-phenylazophenoxy) ethyl]
pyridinium bromide (2b) [24] were prepared according to
the literatures. 4-phenylazophenoxyacetic acid (2a) was
prepared by the Williamson reaction. TNB (3a) was pre-
enzyme
TNB þ CUOOH ꢁ! DTNB þ H2O
The reaction was carried out at 25 °C in PBS (50 mM, pH
7.0) containing 1 lM enzyme and 150 lM TNB, initiated
by the addition of 100 lL of 2.5 mM CUOOH. The initial
rates of the reduction of CUOOH by TNB were determined
by monitoring the disappearance of TNB at 410 nm
0
pared from the 5,5 -dithiol-bis (2-nitrobenzoic acid)
(
DTNB) by reduction with sodium borohydride. All other
reagents were of analytical reagent commercially available
and were used without further purification and all the sol-
vents were dried by normal procedure.
2
1
21
(e410 = 13,600 M cm , pH 7.0 PBS) on a Shimadzu
450 UV-vis spectrophotometer equipped with a temper-
2
2
.2 Synthesis of 4-Phenylazophenoxyacetic Acid (2a)
ature controller.
Sodium hydroxide (0.44 g, 11 mmol) in distilled water
50 mL) was added dropwise to a mixture of 4-phenyl-
azophenol (0.2 g, 1 mmol) and chloroacetic acid (0.94 g,
0 mmol) in 50 mL of distilled water containing 50%
2.5 Spectral Measurements
(
1
H NMR spectra were measured on a Bruker AM-500
1
spectrometer.
ethanol. The mixture was stirred and heated slowly to
boiling and under reflux for 3 h. The solution was acidified
with 2 M hydrochloric acid to pH 5.0. The precipitate was
collected by filtration and rinsed with distilled water to pH
ICD spectra of the inclusions of the 6-ditellurium CD
dimer (1b) with the anionic azobenzene (2a) were obtained
in a 1 cm light path quartz cell at pH 7.0 PBS and 25 °C on
a BioLogic MOS-450 stopped-flow spectrometer equipped
with a temperature controller. ICD was expressed as
ellipticity in millidegree. The concentration of the anionic
azobenzene (2a) was fixed at 0.55 mM; and the concen-
trations of the 6-ditellurium CD dimer (1b) were 0, 0.05,
7
.0. The light brown sheet like crystal recrystallized from
1
ethanol weighs 0.1 g (40%) after dry in vacuum. H NMR
(
300 MHz, (CD ) SO) d = 13.018 (br, 1H), 7.90–7.83 (m,
3
2
4
H), 7.60–7.50 (m, 3H), 7.2 (d, 2H), 4.813 (s, 2H).
0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40 and 0.45 mM
2
.3 Synthesis of 1-[2-(4-Phenylazophenoxy) Ethyl]
Pyridinium Bromide (2b)
respectively.
UV spectra were obtained on a Shimadzu 2450 UV-vis
spectrophotometer equipped with a temperature controller.
Synthesis of [4-(2-Bromo-ethy)-phenyl]-diazene: K CO
2
3
(
0.28 g, 2 mmol) was added with magnetic stirring to 1,2-
dibromoethane (1.9 g, 10 mmol) and 4-phenylazo-phenol
0.2 g, 1 mmol) in 50 mL acetone solution. The solution
2.6 Photoisomerization
(
The sample solutions were irradiated in a quartz cell in the
dark by UV light at 365 nm with a ultraviolet lamp (ZF-7A
16W, Shanghai Gucun Electron Optic Instrument Factory)
was stirred refluxing for 6 h under Ar protection. Finally
the solvent was removed and the combined mixture was
123

6
4
P. Wu et al.
and in a glass cell by visible light with a fluorescent bulb
30 W) at ambient temperature.
(
3
Results and Discussion
3
.1 Design Concept
By the tunable inclusion strategy, molecular machines such
as switchable rotaxanes powered by light through a uni-
versal method of isomerizing azobenzene from the trans
form to the cis and right about have been constructed [26–
2
8]. The same concept can be applied in biological sys-
tems. As known, substrate recognition is an important
factor in the significant acceleration of enzymic reaction
rate and high substrate-specificity. In our previous reports
on artificial GPx, the telluride cyclodextrin dimers exhibit
substrate selectivity for hydroperoxide and thiol substrates.
Imitating the catalytic mechanism of native GPx, the
mimics take advantage of the hydrophobic cavity of
cyclodextrin to recognize and bind the aromatic compound
3
-carboxyl-4-nitrobenzenethiol (TNB, 3a) effectively,
resulting in a great improvement of the catalytic efficiency
10]. However, when the cavities were occupied, the GPx
[
activity was inhibited owing to the lost of the binding
capacity of CD for substrate ROOH or TNB. The fact
above suggests that if the cavities are occupied reversibly
by guest molecules in response to external stimuli, the
catalytic efficiency of the GPx mimics will be controlled
and regulated. Thus, the CD-based artificial enzyme with
an inherent cavity, such as 6-tellurium CD dimer (1a) and
-
1
Fig. 1 a Plots of initial reduction rates m0 (lM s ) of CUOOH with
TNB in the presence of GPx mimic at different concentrations of
azobenzenes. b Plots of relative activities of GPx mimics and their
inclusions with azobenzenes versus the ratios of (azobenzene) to
(
mimic)
6
-ditellurium CD dimer (1b), could be photoregulated by
the inclusion–exclusion reaction of either anionic (2a) or
cationic (2b) azobenzene, respectively.
(Fig. 1a). While the enzyme mimic concentration was fixed
at 1 lM, the initial rate of the 6-tellurium b-CD dimmer
2
1
decreases gradually from 2.24 to the minimum 1.74 lM s
by addition of various concentrations of the anionic azoben-
zenefrom0to2.20 lM. Similarly,eachinitialrateofthe other
three inclusions, the 6-tellurium b-CD dimmer incorporating
the cationic azobenzene (1a–2b, Fig. 1a) and the 6-ditelluri-
um b-CD dimmer incorporating either anionic (1b–2a,
Fig. 1a) or cationic azobenzene (1b–2b, Fig. 1a), declines to
the minimum near the concentration of the azobenzene
2.20 lM, whereas their variation ranges are somewhat
different and the lowest initial rates are 1.89, 2.00 and
3
.2 Evaluating the Photoregulation Capacity
by Activity Assay and Spectroscopy
A controllable enzyme means that its activity could be
regulated, in other words, the activity is inhibited some-
times. Therefore, the photoregulation capacity was first
evaluated by the activity assay. The initial rates (m ) of the
0
reduction of cumene hydroperoxide (CUOOH, 3b) by TNB
in the presence of the GPx mimics were determined in
phosphate buffer (PBS) by monitoring the UV absorption
of TNB at 410 nm (Fig. 1a). The inhibition rate of the
inclusion was represented in the relative activity, which
was deduced respectively based upon the assumption that
the initial rate of the mimic without azobenzene equal to
2
1
2.26 lM s respectively.
In the catalytic cycle, when TNB approaches the mimic,
the negative charge of TNB interacts with the charge of the
azobenzene. Accordingly, such ionic recognition between
the substrate and the enzyme affects the catalytic process.
Thus, TNB approaches the mimic hardly in the mimic
incorporating the anionic azobenzene system, because of
the electrostatic repulsion between TNB and the anionic
azobenzene. By contrast, TNB approaches the mimic rel-
atively easy in the mimic incorporating the cationic
1
00%, as shown in Fig. 1b.
As we anticipated, the CD-based mimics of GPx loose
the activities partly upon addition of azobenzenes, owing to
the lost of binding site of TNB into the cavity of CD
1
23

Photoregulating Catalytic Activity of Cyclodextrin-Based Artificial Glutathione Peroxidase
65
azobenzene system, attributed to the electrostatic attraction
between TNB and the cationic azobenzene. As a result, the
decreased extent of the relative activity of 6-tellurium b-CD
dimmer and 6-ditellurium b-CD dimmer inhibited by the
anionic azobenzene are more than that by the cationic (Fig. 1b).
On the other hand, the catalytic moiety containing tel-
lurium plays an important role in the catalysis as well. As
reported before, the telluride and the ditelluride moieties
represent different catalytic capacity [11]. Thus, when both
mimics are inhibited, they represent different inhibition
rates as shown in Fig. 1b. Although the relative activity of
the mimic has the similar declined tendency with the initial
rate, the declined extent of the relative activity of each
mimic also depends on the catalytic efficiency of the tel-
luride moiety. When the mimics respectively incorporate
either anionic or cationic azobenzene, the decreased extent
of the relative activity of the 6-ditellurium b-CD dimmer is
larger than that of the 6-tellurium b-CD dimmer.
Moreover, Fig. 1 shows other important information.
The maximum inhibition rates of four inclusions are
between 15 and 30%. The highest inhibition rate 28.16%
occurs in the inclusion of the anionic azobenzene with the
1
Fig. 2 H NMR spectra of (2a) in the presence (top) and absence
bottom) of b-CD in D O at ambient temperature
(
2
geometry of the 6-ditellurium b-CD dimmer (1b) with the
anionic azobenzene (2a), since the achiral organic com-
pounds can show an induced circular dichroism (ICD)
signal around their corresponding transition band when they
are in a chiral microenvironment such as the CD cavity [30].
The effect of the 6-ditellurium b-CD dimmer (1b) on the
ellipticity of the anionic azobenzene (2a) is shown in
Fig. 3a. The complex showed a different spectrum from the
inclusion of the azobenzene with the pure CD [31], upon the
addition of the 6-ditellurium b-CD dimmer (1b), when
the concentration of the anionic azobenzene (2a) was fixed
to be 0.55 mM. There are a negative ICD band at 345 nm
assigned to the p ? p* transition of the azobenzene and a
positive ICD band at 470 nm assigned to the n ? p*
transition of the anionic azobenzene (2a) respectively. It
indicates that the anionic azobenzene (2a) enter into the
cavities of the 6-ditellurium b-CD dimmer (1b). Compared
with the anionic azobenzene (2a) alone, a higher concen-
tration of the 6-ditellurium b-CD dimmer (1b) causes the
valley at 345 nm to increase negatively and the peak at
470 nm to increase considerably. Both changes of the
ellipticity caused by the addition of the 6-ditellurium b-CD
dimmer (1b) up to 0.9 equiv are plotted against the ratio of
(1b) to (2a) in Fig. 3b. Both curves at 353 and 470 nm
appear the catastrophe points near the stoichiometric pro-
portion 1:2. Further addition of the 6-ditellurium b-CD
dimmer (1b) causes another increase attributed to the for-
mation of the 1:1 inclusion of the 6-ditellurium b-CD
dimmer (1b) with the anionic azobenzene (2a). These
observations suggest that one 6-ditellurium b-CD dimmer
(1b) can include two anionic azobenzenes (2a), which is
consistent with the activity assay.
6
-ditellurium b-CD dimmer (1b–2a, Fig. 1b) near the mole
ratio of the azobenzene to the mimic at 2:1, due to the lost
of binding site of TNB into the cavity of CD and the
electrostatic repulsion between the negative charges of
TNB and the anionic azobenzene.
Therefore, as a model we took advantage of the largest
inhibition from the inclusion of the anionic azobenzene
(2a) with the 6-ditellurium b-CD dimmer (1b) and intro-
duced light into the enzyme mimic system to regulate the
catalytic activity of the mimic.
To clarify the regioselectivity of the interacting site of
the anionic azobenzene (2a) in the inclusion, we first
compared the shift of each proton of the anionic azobenzene
in the inclusion with the free state [29]. As shown in Fig. 2,
the d value of H protons of the azobenzene unit in excess
a
b-CDs shifts downfield ca. 0.08 ppm, and the d values of
H , H shift upfield ca. 0.13 and 0.05 ppm respectively. The
b
c
d values of H and H shift upfield and the peaks of them
d
e
overlap each other. Since the cavity is less polar than water,
a proton in that environment will be shielded. Upfield shifts
for Hb–e suggest that the protons are in the cavity of
cyclodextrin. Downfield shift for H suggests that ben-
a
zeneoxyl unit is exposed to water moderately. The larger
upfield shift of the protons (H ) in the phenyl ring than the
d
protons (H , H ) in the benzeneoxyl ring indicates that the
b
c
phenyl ring penetrates into the cavity more deeply. It is
inferred that the phenyl ring is the major interacting site of
azobenzene, and the benzeneoxyl ring is located at the
secondary face of cyclodextrin as shown in Scheme 1.
Circular dichroism spectroscopy also provides some
useful information about the inclusion complexation
123

6
6
P. Wu et al.
Scheme 1 The molecule structures of GPx mimics and azobenzenes
left). The reversible photoregulation of artificial GPx process (right).
When one 6-ditellurium b-CD dimmer included two anionic
azobenzenes, the activity of the artificial enzyme was inhibited. After
irradiation with UV light, the cis-isomer azobenzene formed, and
went away from the cavity left an appropriate cavity for accommo-
dating a substrate, as a result, the activity recovered. After irradiation
with visible light, the activity was inhibited over again, owing to that
the trans-isomer azobenzene regenerated, and regressed to the
inclusion
(
3.3 Light Stimulus and Cycle
As shown in Fig. 4a, the absorption of the trans isomer
anionic azobenzenes (trans-2a) at 344 nm is enhanced after
the inclusion with the 6-ditellurium b-CD dimmer (1b) for
the induced motions of electrons of the guest molecules by
the high electron density inside the CD cavity [32]. While
exposed to UV light at 365 nm in a quartz cell, the p ? p*
transition absorption of trans-2a decreases rapidly, the
p ? p* transition absorption peak of the cis isomer of the
anionic azobenzenes (cis-2a) appears concomitantly, and
the photostationary state is reached in 2 min. After that, the
inclusion can undergo cis ? trans photoisomerization to
the photostationary state in 3 min in a glass cell upon visible
light with a fluorescent bulb. The reversible photoisomer-
ization process was cycled many times on alternately irra-
diating the inclusion solution with UV and visible light. The
regeneration of the trans-2a from the cis-2a in the dark was
relatively slow and partly after 1 day at 25 °C. Thus, the
thermal cis ? trans isomerisation during the kinetic mea-
surements (less than 3 min) is negligible.
By the successive irradiation cycles, the catalytic activity
of this inclusion is completely reversible after multiple UV–
Vis irradiation cycles as shown in Fig. 4b. After irradiation
with UV light, the cis-2a formed, and went away from the
cavity left an appropriate cavity for accommodating a sub-
strate, as a result, the GPx activity recovered. After irradiation
with visible light, the GPx activity was inhibited over again,
owing to that the trans-2a regenerated, and regressed to the
inclusion. Such process could be repeated many times as
shown in Scheme 1.
Fig. 3 a ICD spectra of (1b) inclusions with (2a) b Yoe–Jones plots
of the ellipticity at 353 nm (left black) and 470 nm (right blue) versus
the ratio of (1b) to (2a)
These results indicate that a host–guest inclusion com-
plex is formed as shown in Scheme 1 for the possible
binding model.
1
23

Photoregulating Catalytic Activity of Cyclodextrin-Based Artificial Glutathione Peroxidase
67
Acknowledgment Financial support from the Natural Science Foun-
dation of China (No: 20874036, 20921003), the NSFC for Outstanding
Younger Scientist (No. 20725415), the 111 project (B06009) and the
National Basic Research Program (2007CB808006).
References
1
2
3
. Nordberg J, Arner ESJ (2001) Free Radic Bio Med 31:1287
. Arthur J (2000) Cell Mol Life Sci 57:1825
. Toscano MD, Woycechowsky KJ, Hilvert D (2007) Angew Chem
Int Ed 46:3212
4
5
. Reiter R, Wendel A (1985) Biochem Pharmacol 34:2287
. Mirault ME, Tremblay A, Beaudoin N, Tremblay M (1991) J Biol
Chem 266:20752
6
. Ho YS, Magnenat JL, Bronson RT, Cao J, Gargano M, Sugawara
M (1997) J Biol Chem 272:16644
7
8
9
. Dugave C, Demange L (2003) Chem Rev 103:2475
. Tamai N, Miyasaka H (2000) Chem Rev 100:1875
. Ren XJ, Xue Y, Zhang K, Liu JQ, Luo GM, Zheng J, Mu Y, Shen
JC (2001) FEBS Lett 507:377
1
1
0. Dong ZY, Liu JQ, Mao SZ, Huang X, Yang B, Ren XJ, Luo GM,
Shen JC (2004) J Am Chem Soc 126:16395
1. Dong ZY, Liang K, Wang CY, Huang X, Mao SZ, Li XQ, Xu JY,
Liu JQ, Luo GM, Shen JC (2007) J Mol Catal A: Chem 277:193
2. Breslow R, Dong SD (1998) Chem Rev 98:1997
3. Chen Y, Liu Y (2009) Chem Soc Rev 39:495
4. Balzani V, Credi A, Raymo FM, Stoddart JF (2000) Angew
Chem Int Ed 39:3349
5. Harada A (2001) Acc Chem Res 34:456
6. Kaufman H, Vratsanos SM, Erlanger BF (1968) Science 162:1487
7. Willner I, Rubin S (1996) Angew Chem Int Ed 35:367
8. Woolley GA (2005) Acc Chem Res 38:486
1
1
1
1
1
1
1
1
2
Fig. 4 a Photoisomerization spectra of (2a) in the presence (2:1
molar ratio) and absence of (1b) before and after irradiation with UV
light at 365 nm. b Absorbance changes (left black) of the inclusion of
9. Graham CRE-D (2007) Nat Methods 4:619
0. Ueno A, Takahashi K, Osa T (1980) J Chem Soc, Chem Commun
(
1b) with (2a) (1:2, (2a) = 20 lM) at 344 nm, and the catalytic
activity (right blue) changes of the inclusion of (1b) with (2a) (1:2,
1b) = 1 lM) upon alternating irradiation with UV light at 365 nm
and visible light
(
17):837. doi:10.1039/C39800000837
1. Ueno A, Takahashi K, Osa T (1981) J Chem Soc, Chem Commun
3):94. doi:10.1039/C39810000094
2
(
(
2
2
2. Lee W-S, Ueno A (2001) Macromol Rapid Commun 22:448
3. Fu H, Zhou YH, Chen WL, Deqing ZG, Tong ML, Ji LN, Mao
ZW (2006) J Am Chem Soc 128:4924
4. Wang YP, Ma N, Wang ZQ, Zhang X (2007) Angew Chem Int
Ed 46:2823
5. Wu ZP, Hilvert D (1990) J Am Chem Soc 112:5647
4
Conclusion
2
2
In summary, we have provided an example of photoregu-
lating the GPx activity reversibly in a model system that
integrates photoresponsive and catalytic functions by the
supramolecular strategy including both hydrophobic and
electrostatic interactions. The work on photoregulating the
GPx activity more efficiently is undergoing in our lab. It is
anticipated that this work opens a new avenue for manip-
ulating antioxidative enzymes with light for the smart
pharmaceutical design as well as the smart device.
26. Schneider H, Hacket F, Rudiger V, Ikeda H (1998) Chem Rev
8:1755
9
2
2
2
7. Nepogodiev S, Stoddart J (1998) Chem Rev 98:1959
8. Tian H, Wang QC (2006) Chem Soc Rev 35:361
9. Wenz G, Han BH, Muller A (2006) Chem Rev 106:782
30. Shimizu H, Kaito A, Hatano M (1979) Bull Chem Soc Jpn
2:2678
5
3
1. Yoshida N, Yamaguchi H, Higashi M (1994) J Chem Soc, Perkin
Trans 2(12):2507
2. Connors K (1997) Chem Rev 97:1325
3
123