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Hydrolysis of bis(p-nitrophenyl) phosphate promoted by NiII complex of pyrazine-2,5-dicarboxylate
Bkwrganic & bfedicinel Chrrnisq L&fen. Vol. 4, No. 15, pp. 1889-1892,1994 C0pyfight0 1994 Elsevig scieuce Ltd Printedin GreatBritain. All ri@s reserved 0960-894x194 s7.00+0.00
0960-894X(94)00254-
1
Hydrolysis of bis~-Nitroph~nyl) Phosphate Promoted by Ni” Complex of ermine-2,5-di~arboxylate Juaghun
Suh,‘Nowon
Kim, and Hyun
Sook Cho
Department of Chemistry, Seoul National Univewty. Seoul 151-742, Korea
Abstract: The Ni” complex of pyrazine-2,Sdicarboxylate is found to be the best catalyst containing a divalent metal center ever discovered for the hydrolysis of ~s@nitrophenyl) phosphate
Currently, biological
there is much interest
functions
in catalytic
of t~sph~pho~l~on
hydrolysis
reactions
such as info~tion
storage, regulation, signal transduction, and cofactor chemistry.’ hydrolysis
of phosphodiesters
phosphatase,
and phosphomonoesters.
S-nucleotidase.
phosphodiesterase,
of phosphate
esters in connection
with the
storage and processing,
energy
Several metalloenzymes
are known to catalyze
For example, Zn(Il) plays essential roles
fructose-1.6-biphosphatase,
phosphodiesterase,
cyclic
in alkaline nucleotide
and nuclease S, ‘J
Phosphate diesters are very stable against hydrolysis.
Half-lives estimated for the hydrolysis at pH 7 and
25 “c are 10” yr, 2 X 10’ yr, and 2 X lo3 yr for dimethyl phosphate, DNA, and his@-nitrophenyl) (BNPP), respectively!~5
phosphate
The best catalysts synthesized so far for the hydrolysis of BNPP are metal complexes,
and it is widely proposed
that the catalytic reactions proceed through the m~h~isrn
formation of intermediates containing four-membered
of I which involves
rings.6-‘3
In attempts to dekgn effective artificial enzymes for phospliate diester hydrolysis,‘4 we have searched for the structural units to be incorporated into the active sites of the artificial enzymes. such as Cd”2, metalloenzymes
Although the Co”’ derivatives
Cdn 3, and Co”‘4 are among the best catalysts for BNPP hydrolysis, we tried to build artificial using metal ions exploited by biological catalysts.
In addition, Co”‘-based artificial enzymes
may suffer from rate-limiting substrate binding or product dissociation due to the exchange-inertness observed with C!onr complexes.
In search of catalytic centers for artificial metallophosphoesterases,
tested a variety of metal complexes
for
their catalytic activity in the hydrolysis
effective catalysis by the Ni” complex (Ni”5) of ~ne-z~di~~~xyl~ The dissociation method.“‘6
constant (K,) of Ni% was estimated
of BNPP.
= (0.5-l)
(5) is reported = [S], = (l-10)
X 10m5M at pH 6.5-7.5 (0.05 M 4morpholineethanesulfonate
hydroxyethyl)-1-piperazineetharwsulfonate)
we have
In this Letter,
as 1.2 X 1O’6 at 25 *C by the pokrographic
Kinetics of the hydrolysis of BNPP were studied under the conditions of ~iCl,l,,
X lo4 M’ and BNPP],
generally
or N-(2-
and 50 “c. At a given concentration of 5, the pseudo-first-order
rate constant (RJ was proportional to [NiCl,], when [NiCl,], was not greater than [S],. 1889
The K, value indicates
1890
3, sr.IH et ab.
that binding of Ni” to 5 is almost quantitative under these conditions. however,
k, did not increase.
When [NiClJ,
was raised above [S],
The catalytically active species. therefore, is the 1: l-type complex Ni”5.
values of k, were proportional to [Ni”S], at a constant PH. The p~~~io~lity
The
constants (k,,), which represent
the bimolecular rate constants between the Nia5 and BNPP, were measured at pH 6.5-7.5 are summarized Table I. The pH dependence conditions,
hydrolysis
in
of R,, for Ni”g is consistent with the mechanism of 1. ” Under these catalytic
of ~-nitrophenyi
phosphate,
the monoester analogue of BNPP, was found to be much
slower than that of BNPP. Catalytic efficiency of Ni”5 is compared in Table 1 with that of other metal complexes literature. recently
The best catalyst containing prepared
~ly(e~yle~ne)
in this laboratory.‘4
reported in the
divalent metal center reported prior to this work is Co”,[PEI-GO] This catalyst
was prepared
by the Co”-template
condensation
(PEI) with glyoxal and the content of the matal center is 7 residue molar 8 of the polymer.
Using NI*, Cu”, or 2%” ion as the template, Co’,[~-GO], the reduction of Ni”,[PEI-GO]
Cu’JPEf-GO]
with NaBN,, Nf”,~F21-GOJH was obtained.
or Zn”,fPEI-GO]
was prepared.
BNPP Co”‘3
Zn”6
H
Co”,IPEf-GO]
Ii
H
Ni”,[PEI-GO]H
H’
-H
Cu”,[PET-GO]
By
Except the macrocyclic complexes
built on PEI, Znn6 and Zn”? are the most effective catalysts containing divalent metal centers reported to date.
H
of
H
H
Zn”2[PEI-GOJ
Hydrolysis
of bis(p-nitrophenyl)
1891
phosphate
Table 1. Values of Kinetic Parameters for BNPP Hydrolysis Catalyzed by Various Complexes
PH 6.5
parameter value*
ref
k,, = 0.036 M-‘s-l
this study
50
7.0
k br- - 0 . 29 M-‘s-’
this study
50
7.5
k,, = 0.084 M-‘s-’
this study
50
6.5-7.5
k b, = 2.5 M-‘s-’
kmp Ni”5
50
corn 2
5
corn 3
50
6.5-7.5
k b, = 0.46 M-‘s-l
5
Co” 4
50
6.5-7.5
kta-- 8 . 1 X 103M-1s-1
5
Co”’ (en&
50
7
A,, = 2.7 X 10.’ M-‘s”
7
Corn (trien)
50
7
k b, = 4 . 8 X 1O-2M-‘s-’
7
Co” (dien)
50
7
k h < 1 X l@M-‘s-’
7
Znn6
35
> 8.5
k b, = 8.5 X lCt’ M-‘s-’
11
Znn7
35
> 10
kbl-- 2 ’ 1 X l@M-‘s-l
11
Ni(tren)‘+
75
8.6
&fold acceleration, C, = 0.1 mM
13
Ni(bpy),‘+
75
8.6
7-fold acceleration, C, = 0.1 mM
13
Cu(bpy)‘+
75
8.6
20-fold acceleration, C, = 0.1 mM
13
Zn(bpy)‘+
75
8.6
2-fold acceleration, C, = 0.1 mM
13
Co”,[PEI-GO]
50
7.5
k bl- 0.18 M-‘s-l
14
Ni’,[PEI-GO]H
50
6.5
Ab, = ca 5 X lO-‘M-‘s-l
14
Cu”,[PBI-GO]
50
6.5
kbr--
14
Zn”,[PBI-GO]
50
7.5
kbi= 7.4 X 1O-3M-‘s”
14
spontaneous
50
7.0
k o-- 3 X 10Los-’
5
OH-
35
k b, = 2.4 X l@M-‘s-’
11
‘Parameters k, and k, stand for the first-order and the second-order
rate constants, respectively.
When judged with A,,, Ni”5 is the best catalyst containing a divalent metal center ever discovered BNPP hydrolysis
and is comparable to Corn 3, the second best Co’” -catalyst.
Other Ni” complexes
for
such as
Ni(tren)‘+ or Ni(bpy)t+ are practically ineffective in BNPP hydrolysis (Table 1). Our study indicated that the Ni” complex of pyrazine-2-carboxylate
did not catalyze BNPP hydrolysis. The reason why the Ni” complex of
5 is much more effective than other Ni” complexes is not clear. As revealed by the data s ummarired in Table 1, the catalytic efficiency of the Co’” complexes is greatly affected by the ligand structure. to bond angles in the transition state containing a four-membered
ring.6
efficiency between the Ni” complexes of 5 and pyrazine-2-carboxylate
This has been attributed
The remarkable difference in catalytic suggests that both electronic and steric
effects exerted by the ligands affect the catalytic power of metal complexes. In order to design artificial enzymes necessary
to incorporate
which reproduce
important
features of enzymatic
actions, it is
effective catalytic centers into the backbone of the artificial enzymes.‘4~18~23In the
previously reported artificial metahophosphoesterases
built on PBI, the macrocyclic centers were constructed by
1892
J. SUB et al.
random condensation
of PEI with dicarbonyl compounds
in the presence of metal ionsI
The structures of
catalytic centers of the PEI-based macrocycles such as Co”.,[PEI-GO] are not clearly known. the catalytic
site on Ni”5 is well defined
and Nil’5 may be exploited
as catalytic
On the other hand, centers
of artificial
metallophosphoesterases. Acknowledgment.
This work was supported by Basic Science Research Institute Program (1994). R.O.K.
Ministry of Education and the Organic Chemistry Research Center.
References 1.
and
Notes
Dugas, H. In Bioorganic Chemistry. A Chemical Approach to Enzyme Action, Springer-Verlag:
New
York, 1989; 2nd ed.; Chapters 3.4 and 5. 2.
Vallee, B. L. In Zinc Enzymes,
Bertini, I.; Luchinat, C.; Maret. W.; Zeppezauer,
M. Ed.; Birkhiiuser:
Boston, 1986, Chap. 1. 3.
Dive, V. ; Y iotakis, A.; Toma, F. In Zinc Enzymes,
Bertini, I.; Luchinat, C.; Maret, W.; Zeppezauer. M.
Ed.; Birkhiiuser: Boston, 1986; Chap. 20. 4.
Kim, J. H.; Chin, J. J. Am. Chem. Sot. 1992, 114, 9792.
5.
Chin, J.; Banaszczyk, M.; Jubian. V.; Zou, X. J. Am. Chem. Sot. 1989, 111, 186.
6.
Chm. J. Act. Chem. Res. 199 1, 24, 145.
7.
Chin, J.; Zou, X. J. Am. Chem. Sot. 1988,
8.
Anderson, Gem.
9.
Sot.
B.; Milbum.
110, 223.
R. M.; Harrowfield,
J. MacB.. Robertson,
G. B.; Sargeson.
A. M. J. Am.
1977, 99, 2652. 1983, 105, 7327.
Jones, D. R.; Lindoy, L. F.; Sargeson, A. M. J. Am. Chem. Sot.
10.
Hendry, P.; Sargeson, A. M. J. Am. Chem. Sot. 1989, 111, 2521.
11.
Koike, T.; Kimura, E. J. Am. Gem.
12.
Hendry, P.; Sargeson, A. M. Inorg. Chem. 1990, 29, 97.
13.
De Rosch and Trogler, Inorg. Chem. 1990. 29. 2409.
Sot.
199 1, 113, 8935.
1994, 59. 1561.
14.
Kim, N.. Suh. J. J. Org. Gem.
15.
Bard, A: Faulker, L. R. In Electrochemical Me&oak, Wiley: New York, 1980, pp. 218-221.
16.
Gao, X.; Zhang, M. Anal. Chem. 1984,56.
17.
In this mechanism, one of the two aqua ligands of the metal ion is to be unionized to bind the substrate and
1912.
the other be ionized to form the nucleophilic
hydroxo group.
This mechanism
predicts, therefore,
a
bell-shaped pH profile of the catalytic activity as observed in this study (Table 1).6 18.
Suh, J. Act. Chem. Rex 1992, 25, 273.
19.
Suh, J.; Cho, Y. Lee. K. J. J. Am. Chem. Sot. 1991, 113, 4198.
20.
Suh, J.; Lee, S. H.; Zoh, K. D. J. Am. Chem. Sot.
21.
Suh, J.. Kim, N. J. Org. Chem. 1993.58,
22.
Lee, K. J.; Suh, J. Bioorg. Chem. 1994. 22, 95.
23.
Suh, J. In Perspective on Bioinorganic Chemistry, Hay, R. W.; Dilworth, J. R.; Nolan, K. B Ed.; JAI
1992, 114, 7961.
1284.
Press: Greenwich; Vol. 3, in press.
(Received in Japan 24 May 1994; accepted 24 June 1994)
0960-894X(94)00254-
1
Hydrolysis of bis~-Nitroph~nyl) Phosphate Promoted by Ni” Complex of ermine-2,5-di~arboxylate Juaghun
Suh,‘Nowon
Kim, and Hyun
Sook Cho
Department of Chemistry, Seoul National Univewty. Seoul 151-742, Korea
Abstract: The Ni” complex of pyrazine-2,Sdicarboxylate is found to be the best catalyst containing a divalent metal center ever discovered for the hydrolysis of ~s@nitrophenyl) phosphate
Currently, biological
there is much interest
functions
in catalytic
of t~sph~pho~l~on
hydrolysis
reactions
such as info~tion
storage, regulation, signal transduction, and cofactor chemistry.’ hydrolysis
of phosphodiesters
phosphatase,
and phosphomonoesters.
S-nucleotidase.
phosphodiesterase,
of phosphate
esters in connection
with the
storage and processing,
energy
Several metalloenzymes
are known to catalyze
For example, Zn(Il) plays essential roles
fructose-1.6-biphosphatase,
phosphodiesterase,
cyclic
in alkaline nucleotide
and nuclease S, ‘J
Phosphate diesters are very stable against hydrolysis.
Half-lives estimated for the hydrolysis at pH 7 and
25 “c are 10” yr, 2 X 10’ yr, and 2 X lo3 yr for dimethyl phosphate, DNA, and his@-nitrophenyl) (BNPP), respectively!~5
phosphate
The best catalysts synthesized so far for the hydrolysis of BNPP are metal complexes,
and it is widely proposed
that the catalytic reactions proceed through the m~h~isrn
formation of intermediates containing four-membered
of I which involves
rings.6-‘3
In attempts to dekgn effective artificial enzymes for phospliate diester hydrolysis,‘4 we have searched for the structural units to be incorporated into the active sites of the artificial enzymes. such as Cd”2, metalloenzymes
Although the Co”’ derivatives
Cdn 3, and Co”‘4 are among the best catalysts for BNPP hydrolysis, we tried to build artificial using metal ions exploited by biological catalysts.
In addition, Co”‘-based artificial enzymes
may suffer from rate-limiting substrate binding or product dissociation due to the exchange-inertness observed with C!onr complexes.
In search of catalytic centers for artificial metallophosphoesterases,
tested a variety of metal complexes
for
their catalytic activity in the hydrolysis
effective catalysis by the Ni” complex (Ni”5) of ~ne-z~di~~~xyl~ The dissociation method.“‘6
constant (K,) of Ni% was estimated
of BNPP.
= (0.5-l)
(5) is reported = [S], = (l-10)
X 10m5M at pH 6.5-7.5 (0.05 M 4morpholineethanesulfonate
hydroxyethyl)-1-piperazineetharwsulfonate)
we have
In this Letter,
as 1.2 X 1O’6 at 25 *C by the pokrographic
Kinetics of the hydrolysis of BNPP were studied under the conditions of ~iCl,l,,
X lo4 M’ and BNPP],
generally
or N-(2-
and 50 “c. At a given concentration of 5, the pseudo-first-order
rate constant (RJ was proportional to [NiCl,], when [NiCl,], was not greater than [S],. 1889
The K, value indicates
1890
3, sr.IH et ab.
that binding of Ni” to 5 is almost quantitative under these conditions. however,
k, did not increase.
When [NiClJ,
was raised above [S],
The catalytically active species. therefore, is the 1: l-type complex Ni”5.
values of k, were proportional to [Ni”S], at a constant PH. The p~~~io~lity
The
constants (k,,), which represent
the bimolecular rate constants between the Nia5 and BNPP, were measured at pH 6.5-7.5 are summarized Table I. The pH dependence conditions,
hydrolysis
in
of R,, for Ni”g is consistent with the mechanism of 1. ” Under these catalytic
of ~-nitrophenyi
phosphate,
the monoester analogue of BNPP, was found to be much
slower than that of BNPP. Catalytic efficiency of Ni”5 is compared in Table 1 with that of other metal complexes literature. recently
The best catalyst containing prepared
~ly(e~yle~ne)
in this laboratory.‘4
reported in the
divalent metal center reported prior to this work is Co”,[PEI-GO] This catalyst
was prepared
by the Co”-template
condensation
(PEI) with glyoxal and the content of the matal center is 7 residue molar 8 of the polymer.
Using NI*, Cu”, or 2%” ion as the template, Co’,[~-GO], the reduction of Ni”,[PEI-GO]
Cu’JPEf-GO]
with NaBN,, Nf”,~F21-GOJH was obtained.
or Zn”,fPEI-GO]
was prepared.
BNPP Co”‘3
Zn”6
H
Co”,IPEf-GO]
Ii
H
Ni”,[PEI-GO]H
H’
-H
Cu”,[PET-GO]
By
Except the macrocyclic complexes
built on PEI, Znn6 and Zn”? are the most effective catalysts containing divalent metal centers reported to date.
H
of
H
H
Zn”2[PEI-GOJ
Hydrolysis
of bis(p-nitrophenyl)
1891
phosphate
Table 1. Values of Kinetic Parameters for BNPP Hydrolysis Catalyzed by Various Complexes
PH 6.5
parameter value*
ref
k,, = 0.036 M-‘s-l
this study
50
7.0
k br- - 0 . 29 M-‘s-’
this study
50
7.5
k,, = 0.084 M-‘s-’
this study
50
6.5-7.5
k b, = 2.5 M-‘s-’
kmp Ni”5
50
corn 2
5
corn 3
50
6.5-7.5
k b, = 0.46 M-‘s-l
5
Co” 4
50
6.5-7.5
kta-- 8 . 1 X 103M-1s-1
5
Co”’ (en&
50
7
A,, = 2.7 X 10.’ M-‘s”
7
Corn (trien)
50
7
k b, = 4 . 8 X 1O-2M-‘s-’
7
Co” (dien)
50
7
k h < 1 X l@M-‘s-’
7
Znn6
35
> 8.5
k b, = 8.5 X lCt’ M-‘s-’
11
Znn7
35
> 10
kbl-- 2 ’ 1 X l@M-‘s-l
11
Ni(tren)‘+
75
8.6
&fold acceleration, C, = 0.1 mM
13
Ni(bpy),‘+
75
8.6
7-fold acceleration, C, = 0.1 mM
13
Cu(bpy)‘+
75
8.6
20-fold acceleration, C, = 0.1 mM
13
Zn(bpy)‘+
75
8.6
2-fold acceleration, C, = 0.1 mM
13
Co”,[PEI-GO]
50
7.5
k bl- 0.18 M-‘s-l
14
Ni’,[PEI-GO]H
50
6.5
Ab, = ca 5 X lO-‘M-‘s-l
14
Cu”,[PBI-GO]
50
6.5
kbr--
14
Zn”,[PBI-GO]
50
7.5
kbi= 7.4 X 1O-3M-‘s”
14
spontaneous
50
7.0
k o-- 3 X 10Los-’
5
OH-
35
k b, = 2.4 X l@M-‘s-’
11
‘Parameters k, and k, stand for the first-order and the second-order
rate constants, respectively.
When judged with A,,, Ni”5 is the best catalyst containing a divalent metal center ever discovered BNPP hydrolysis
and is comparable to Corn 3, the second best Co’” -catalyst.
Other Ni” complexes
for
such as
Ni(tren)‘+ or Ni(bpy)t+ are practically ineffective in BNPP hydrolysis (Table 1). Our study indicated that the Ni” complex of pyrazine-2-carboxylate
did not catalyze BNPP hydrolysis. The reason why the Ni” complex of
5 is much more effective than other Ni” complexes is not clear. As revealed by the data s ummarired in Table 1, the catalytic efficiency of the Co’” complexes is greatly affected by the ligand structure. to bond angles in the transition state containing a four-membered
ring.6
efficiency between the Ni” complexes of 5 and pyrazine-2-carboxylate
This has been attributed
The remarkable difference in catalytic suggests that both electronic and steric
effects exerted by the ligands affect the catalytic power of metal complexes. In order to design artificial enzymes necessary
to incorporate
which reproduce
important
features of enzymatic
actions, it is
effective catalytic centers into the backbone of the artificial enzymes.‘4~18~23In the
previously reported artificial metahophosphoesterases
built on PBI, the macrocyclic centers were constructed by
1892
J. SUB et al.
random condensation
of PEI with dicarbonyl compounds
in the presence of metal ionsI
The structures of
catalytic centers of the PEI-based macrocycles such as Co”.,[PEI-GO] are not clearly known. the catalytic
site on Ni”5 is well defined
and Nil’5 may be exploited
as catalytic
On the other hand, centers
of artificial
metallophosphoesterases. Acknowledgment.
This work was supported by Basic Science Research Institute Program (1994). R.O.K.
Ministry of Education and the Organic Chemistry Research Center.
References 1.
and
Notes
Dugas, H. In Bioorganic Chemistry. A Chemical Approach to Enzyme Action, Springer-Verlag:
New
York, 1989; 2nd ed.; Chapters 3.4 and 5. 2.
Vallee, B. L. In Zinc Enzymes,
Bertini, I.; Luchinat, C.; Maret. W.; Zeppezauer,
M. Ed.; Birkhiiuser:
Boston, 1986, Chap. 1. 3.
Dive, V. ; Y iotakis, A.; Toma, F. In Zinc Enzymes,
Bertini, I.; Luchinat, C.; Maret, W.; Zeppezauer. M.
Ed.; Birkhiiuser: Boston, 1986; Chap. 20. 4.
Kim, J. H.; Chin, J. J. Am. Chem. Sot. 1992, 114, 9792.
5.
Chin, J.; Banaszczyk, M.; Jubian. V.; Zou, X. J. Am. Chem. Sot. 1989, 111, 186.
6.
Chm. J. Act. Chem. Res. 199 1, 24, 145.
7.
Chin, J.; Zou, X. J. Am. Chem. Sot. 1988,
8.
Anderson, Gem.
9.
Sot.
B.; Milbum.
110, 223.
R. M.; Harrowfield,
J. MacB.. Robertson,
G. B.; Sargeson.
A. M. J. Am.
1977, 99, 2652. 1983, 105, 7327.
Jones, D. R.; Lindoy, L. F.; Sargeson, A. M. J. Am. Chem. Sot.
10.
Hendry, P.; Sargeson, A. M. J. Am. Chem. Sot. 1989, 111, 2521.
11.
Koike, T.; Kimura, E. J. Am. Gem.
12.
Hendry, P.; Sargeson, A. M. Inorg. Chem. 1990, 29, 97.
13.
De Rosch and Trogler, Inorg. Chem. 1990. 29. 2409.
Sot.
199 1, 113, 8935.
1994, 59. 1561.
14.
Kim, N.. Suh. J. J. Org. Gem.
15.
Bard, A: Faulker, L. R. In Electrochemical Me&oak, Wiley: New York, 1980, pp. 218-221.
16.
Gao, X.; Zhang, M. Anal. Chem. 1984,56.
17.
In this mechanism, one of the two aqua ligands of the metal ion is to be unionized to bind the substrate and
1912.
the other be ionized to form the nucleophilic
hydroxo group.
This mechanism
predicts, therefore,
a
bell-shaped pH profile of the catalytic activity as observed in this study (Table 1).6 18.
Suh, J. Act. Chem. Rex 1992, 25, 273.
19.
Suh, J.; Cho, Y. Lee. K. J. J. Am. Chem. Sot. 1991, 113, 4198.
20.
Suh, J.; Lee, S. H.; Zoh, K. D. J. Am. Chem. Sot.
21.
Suh, J.. Kim, N. J. Org. Chem. 1993.58,
22.
Lee, K. J.; Suh, J. Bioorg. Chem. 1994. 22, 95.
23.
Suh, J. In Perspective on Bioinorganic Chemistry, Hay, R. W.; Dilworth, J. R.; Nolan, K. B Ed.; JAI
1992, 114, 7961.
1284.
Press: Greenwich; Vol. 3, in press.
(Received in Japan 24 May 1994; accepted 24 June 1994)