2P054
ࠈࠈࠈࠈ㕪-࢛࢞ࢮ࣎ࣜࣆ࢔ࣛࣤ㘊మࡡཬᚺᛮ࡞࠽ࡄࡾ㒼నᏄຝᯕ
ࠈࠈࠈ(ஐኬ඙ᑙ◂)ࠈ ࠈ‫ྡྷې‬㔕ᬓ஁ࠉⵞờ㧏ᚷࠉྚ⃕ୌᠺ
࠘ᗆㄵ࠙
ࢲࢹࢠ࣑ࣞ P450 ࡢࠉ࣓ࢿ࢛࢞ࢨ
H O H
N
ࢣࢻ࣭ࢭᵕᘟࡡ㓗⣪῟ຊ㓕⣪Ὡᛮࢅ
N
3+
Fe
N
Cys
ROH
᭯ࡌࡾୌ⩄ࡡࣉ࣑ࢰࣤࣂࢠ㈻࡚ࠉ㑇
S
RH
N
Fe
N
N
H2O
Cys
N
3+
S
N
e–
O
N
ඔᆵ࠿ୌ㓗໩⅛⣪࡛⤎ྙࡊ࡙ 450 nm
+･ Fe
N
࡞ᴗኬࢅࡵࡗ≁ᚡⓏ࡝ྺ཭ࢪ࣋ࢠࢹ
N
4+
S
N
Cys
N
OH
3+
Cys
S
H+
N
N
Fe
N
Cys
hydroperoxo種
ࡊ഼࡙ࡂ࡛⩻࠻ࡼࡿ࡙࠷ࡾࠊ
O
N
Fe
N
I ࡛┤␆ࡌࡾ㸞࠿⏍ᠺࡊࠉὩᛮ⛸࡛
Cys
+
O
࣎ࣜࣆ࢔ࣛࣤ㘊మ㸝௧ୖࠉCompound
N
H
H2O
ࣜࢅ♟ࡌࠊࡆࡡὩᛮࢦ࢕ࢹ࡞࢛࢞ࢮ
N
Compound I
oxo種
O–
3+
S
O
N
N
N
–
e
Fe
N
Cys
O
S
N
O2
N
2+
S
N
Fe2+
N
peroxo種
ᅒ 1. P450 ࡡり፳ࢦ࢕ࢠࣜ
ࠈᅒ 1 ࡞ࠉࡐࡡり፳ࢦ࢕ࢠࣜࢅ♟ࡌࠊ
ࡱࡍࠉิ᭿≟ឺࡡ Fe3+ࣉ࣑㕪࡞ᇱ㈻࠿⤎ྙࡊࠉỀฦᏄ࠿㞫⬲ࡌࡾࠊࡐࡿ࡞ఔ࠷ࠉࣉ࣑㕪ࡡୌ㞹Ꮔ
㑇ඔ࠿㉫ࡆࡽࠉ├ࡔ࡞㓗⣪ฦᏄ࠿ࣉ࣑࡞㒼నࡌࡾࠊḗ࡞ࠉ2 ᅂ┘ࡡୌ㞹Ꮔ㑇ඔ࠿㉫ࡆࡽࠉ㕪࡞㒼
నࡊ࡙࠷ࡾࢪ࣭ࣂ࣭࢛࢞ࢨࢺ࠿࢛࣋ࣜ࢞ࢨࢺ(O2-)࡞㌹ᥦࡈࡿࡾࠊࡆࡡ peroxo ⛸࠿ࣈࣞࢹࣤࡡ౩୙
ࢅུࡄࡾࡆ࡛࡚ࠉhydroperoxo ⛸ࢅ⤊࡙ࠉ㓗໩Ὡᛮ⛸࡚࠵ࡾ Compound I ࠿⏍ᠺࡌࡾ࡛⩻࠻ࡼࡿ࡙
࠷ࡾࠊ
ࠈNam ࡼࡢࠉCompound I ࡡ࣓ࢸࣜ㘊మ࡚࠵ࡾ Fe(TPP)X (TPP = meso-tetraphenylporphinato and
X– = anionic ligand)ࢅྙᠺࡊࠉPhIO ࡷࣈࣞࢹࣤᛮ⁈፳୯࡚ H2O2 ࡛ཬᚺࡈࡎࡾࡆ࡛࡚࢛࢞ࢮ⛸
࠿⏍ᠺࡌࡾࡆ࡛ࢅ☔ヾࡊࡒࠊࡆࡡ㘊మ࡞࠽ࡄࡾ㍂㒼నᏄࡡຝᯕ࡞ࡗ࠷࡙᳠ゞࢅ⾔ࡖࡒ⤎ᯕࠉ
Cl– ࢅ㍂㒼నᏄ࡛ࡊ࡙⏕࠷ࡒ࡛ࡀࡡ࡮࠹࠿ SO3CF3–࡞Ẓ࡬ࠉཬᚺᛮ࠿㧏࠷࡛࠷࠹⤎ᯕ࠿ᚋࡼࡿ
ࡒ [1] ࠊ ࡆ ࡡ 㐢࠷ ࠿ ⏍ ࡋࡾ ⌦ ⏜ ࡛ࡊ ࡙ ࠉ “Push–Pull” ຝ ᯕ ࠿㔔 さ ࡛ ⩻࠻ ࡼ ࡿ ࡙࠷ ࡾ ࠊ ࡆࡆ ࡚
“Push–Pull”ຝᯕ࡞ࡗ࠷࡙ࠉ⠾༟࡞ㄕ᪺ࡌࡾࠊSligar ࡼࡢࠉP450cam ࡡࣉ࣑㎾എࡡ⤎ᬏᵋ㏸࠾ࡼࠉ
ᅒ 2 ࡞♟ࡌࡻ࠹࡞ࠉAsp251ࠉThr252 ࠽ࡻࡦỀฦᏄ㛣࡚ࡡỀ
⣪⤎ྙࢅฺ⏕ࡊࡒࣈࣞࢹࣤࢾࢴࢹ࣭࣠ࢠ
[3]
࡛ Cys ⏜ᮮࡡ࢓
251
ࢼ࢛ࣤᛮࡡࢲ࢛࣭ࣝࢹ࡞ࡻࡾ㞹Ꮔ౩⤝ࡡ⤄ࡲྙࢂࡎ
(“Push–Pull”ຝᯕ)࡞ࡻࡖ࡙ O–O ⤎ྙࡡ㛜⿛࠿ಀ㐅ࡈࡿࠉ
252
Compound I ࡡ⏍ᠺ࠿ኬࡀࡂಀ㐅ࡈࡿ࡙࠷ࡾ࡛᥆ᏽࡊࡒࠊࡐ
ࡆ࡚ࠉᮇ◂✪࡚ࡢࠉCompound I ࡡ㍂㒼నᏄ࡛ࡊ࡙㞹Ꮔば࿰
ງࡡ␏࡝ࡾᵕࠍ࡝㝔࢕࢛ࣤࢅ㐽ᢝࡊࠉࡐࡡཬᚺᛮࡡ㐢࠷࠾
ࡼ”Push”ຝᯕ࡞ࡗ࠷࡙⌦ㄵⓏ࡞よ᪺ࡊࡒࠊ
ᅒ 2. “Push–Pull”ຝᯕ(P450cam)[2]
࠘ゝ⟤᪁Ἢ࠙
ࠈᵋ㏸᭩㐲໩࠽ࡻࡦᣲິよᯊ࡞ࡢࠉᐠᗐỏ㛭ᩐࡡࡥ࡛ࡗ࡚࠵ࡾ B3LYP Ἢࠉᇱᗇ㛭ᩐ࡛ࡊ࡙㕪ཋ
Ꮔ࡞ࡢ TZV ᇱᗇࢅࠉ௙ࡡཋᏄ࡞ᑊࡊ࡙ࡢ D95 ᇱᗇࢅ⏕࠷ࡒࠊධ࡙ࡡゝ⟤࡞ࡢࠉGaussian03 ࣈࣞ
ࢡ࣑ࣚࢅ⏕࠷ࡒࠊ㞹Ⲭࡢ 0ࠉࢪࣅࣤኣ㔔ᗐࡢ 2 㔔㡧࡛ 4 㔔㡧ࢅ⏕࠷࡙ゝ⟤ࢅ⾔ࡖࡒࠊ㍂㒼నᏄ࡛
ࡊ࡙ࠉOH– ࠉOAc– ࠉCl– ࠉSO3CF3– ࢅ⏕࠷ࠉ࢓ࣜ࢜ࣤࡡỀ㓗໩ཬᚺࡡᚂ㏷㐛⛤࡚࠵ࡾỀ⣪ᘤࡀᢜࡀ
㐛⛤࡞ࡗ࠷࡙ࡐࡡ࢙ࢾ࣭ࣜ࢟ን໩ࢅぜ✒ࡵࡖࡒࠊࡱࡒࠉᇱ㈻࡞ࡢᐁ㥺࡚⏕࠷ࡼࡿ࡙࠷ࡾࢨࢠࣞࣉ
࢞ࢦࣤࢅ㐽ᢝࡊࡒࠊ
࠘⤎ᯕ࡛⩻ᐳ࠙
ࠈᅒ 3 ࡢ㍂㒼నᏄ OH–ࢅࡵࡗ࣓ࢸࣜ㘊మࡡ࢛࢞ࢮ㒼నᏄ࡞
H
H
ࡻࡽࢨࢠࣞࣉ࢞ࢦࣤࡡ C–H ⤎ྙ࠾ࡼỀ⣪ཋᏄ࠿ᘤࡀᢜ࠾ࡿ
C
H
H
C
C
H
Fe–O ⤎ྙ㛏࠿ 1.815ύࠉ࢛࢞ࢮ㒼నᏄ࡛ࢨࢠࣞࣉ࢞ࢦࣤࡡ
࣭ࡢࠉࡐࡿࡑࡿ 11.0 kcal/molࠉ12.6 kcal/molࠉ15.4 kcal/mol
࡛ịࡴࡼࡿࡒࠊࡱࡒࠉ㞹Ꮔば࿰ງࡢࠉB3LYP/6-311++G**ࣝ
࡚࣊ࣜ 40.8 kcal/molࠉ73.0 kcal/molࠉ85.9 kcal/molࠉ119.4
kcal/mol ࡚࠵ࡖࡒࠊࡆࡿࡼࡡ㛭౿ࢅᅒ♟ࡌࡾ࡛ࠉᅒ 4 ࡡࡻ
࠹࡞࡮࡯├⥲Ⓩ࡞࡝ࡾࡆ࡛࠿ึ᪺ࡊࡒࠊࡆࡿࡢ㞹Ꮔば࿰ງ
ࡡ఩࠷㍂㒼నᏄ࡮࡜ࠉゕ࠷ᥦ࠻ࡿࡣ㞹Ꮔ౩୙ᛮ࠿㧏࠷㍂㒼
H
C
C
C
H
O
H
C
C
C
H
r(Fe-N)avg= 2.022
H
ᅒ 3. 㒼నᏄE=9.3kcal/mol
OH–ࢅ⏕࠷ࡒ࣓ࢸࣜࡡ
㐼⛛≟ឺࡡ᭩㐲໩ᵋ㏸
16
SO CF
3
15
活性化エネルギー(kcal/mol)
నᏄ OAc ࠉCl ࠉSO3CF3 ࢅ⏕࠷ࡒ࣓ࢸࣜࡡὩᛮ໩࢙ࢾࣜ࢟
C
N
C
H
C
N
N
C
H
1.815
ࡾὩᛮ໩࢙ࢾ࣭ࣜ࢟ࡢࠉ4 㔔㡧࡚ 9.3 kcal/mol ࡚࠵ࡽࠉ㍂㒼
–
H
Fe
C
C
H
H
C
C
N
C
C
H
O
C
C
C
H
–
C
1.803
H
–
C
1.253
H
1.301
ࣤࡡ C–H ⤎ྙ㛏࠿ 1.253ύࠉ࢛࢞ࢮ㒼నᏄഁࡡ Fe–O ⤎ྙ
Ề⣪ཋᏄ࡛ࡡ㊝㞫࠿ 1.301ύ࡚࠵ࡖࡒࠊࡆࡡ㐼⛛≟ឺ࡞࠽ࡄ
HH
C
HH
ࡾ㝷ࡡ㐼⛛≟ឺࡡ᭩㐲໩ᵋ㏸ࢅ♟ࡊ࡙࠷ࡾࠊࢨࢠࣞࣉ࢞ࢦ
㛏࠿ 1.803ύࠉFe–N ࡡᖲᆍ⤎ྙ㛏࠿ 2.022ύࠉ㍂㒼నᏄഁࡡ
H
C
H
3
14
13
Cl
12
-
-
11
OAc
10
-
OH
9
40
50
60 70 80 90 100 110 120
電子親和力(kcal/mol)
ᅒ 4. 㞹Ꮔば࿰ງࡡ␏࡝ࡾ㒼నᏄࢅ⏕࠷ࡒ
࣓ࢸࣜ࡞ࡻࡾὩᛮ໩࢙ࢾ࣭ࣜ࢟ࡡẒ㍉
నᏄ࡮࡜ Compound I ࡡཬᚺᛮࢅቌຊࡈࡎࡾࡆ࡛ࢅ♟ࡊ࡙࠷
ࡾࠊࡱࡒࠉᵋ㏸ࡡⅤ࠾ࡼぜ࡙ࡲࡾ࡛ࠉCompound I ࡡ Fe–O ⤎ྙ㛏ࡢࠉ୕ࡡ㍂㒼నᏄ࡞ᑊࡊ࡙ࡐࡿ
ࡑࡿ 1.803ύࠉ1.665ύࠉ1.659ύࠉ1.655ύ࡛ịࡴࡼࡿࡒࠊࡆࡿࡢ࢛࢞ࢮ㒼నᏄ࡞㍂㒼నᏄ࠾ࡼ㞹
Ꮔ࠿Ὦࡿ㎲ࡳࡆ࡛࡞ࡻࡖ࡙ࠉ࢛࢞ࢮ୕ࡡࢪࣅࣤᐠᗐ࠿ቌࡊࠉFe–O ⤎ྙࡡ⤎ྙ㛏࠿ቌຊࡌࡾࡒࡴ
࡛⩻࠻ࡼࡿࡾࠊࡆࡿࡼࡡ⤎ᯕ࠾ࡼࠉ㍂㒼నᏄࡡ㞹Ꮔ౩୙ຝᯕ(“Push”ຝᯕ)ࡡᙁࡈ࡞ࡻࡽ Compound
I ࡡཬᚺᛮ࠿ቌ΅ࡌࡾࡆ࡛࠿᪺ࡼ࠾࡛࡝ࡖࡒࠊ
࠘ᘤ⏕ᩝ⊡࠙
[1] Nam, W.; Jin, S. W.; Lim, M. H.; Ryu, J. Y.; Kim, C. Inorg. Chem. 2002, 41, 3647.
[2] Sono, M.; Roach, M. P.; Coulter, E. D.; Dawson, J. H. Chem. Rev. 1996, 96, 2841.
[3] (a) Gerber, N. C.; Sligar, S. G. J. Am. Chem. Soc. 1992, 114, 8742. (b) Gerber, N, C.; Sligar, S. G. J. Biol. Chem. 1994, 269, 4260.

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