Enhanced geminate ligand rebinding upon photo-dissociation of silica gel-embedded myoglobin-CO

被引:24
作者
Abbruzzetti, S
Viappiani, C
Bruno, S
Mozzarelli, A
机构
[1] Univ Parma, Dipartimento Biochim & Biol Mol, I-43100 Parma, Italy
[2] Univ Parma, Dipartimento Fis, I-43100 Parma, Italy
[3] Univ Parma, Ist Nazl Fis Mat, I-43100 Parma, Italy
关键词
D O I
10.1016/S0009-2614(01)01027-2
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We have investigated the kinetics of ligand rebinding after nano-second laser photolysis of horse heart carboxymyoglobin, encapsulated in wet silica gels. The geminate ligand rebinding to the gel embedded protein shows a markedly enhanced efficiency, 0.43, with respect to solution. This geminate phase can be described by a stretched exponential decay. The second-order rate of CO rebinding to myoglobin (Mb) gels is 1.42 x 10(6) M-1 s(-1). The bimolecular binding rate is thermally activated with barriers of approximately 4 kcal mol(-1). These findings indicate that Mb within silica gels is in an environment with an apparent higher local viscosity than in solution. (C) 2001 Elsevier Science BN. All rights reserved.
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页码:430 / 436
页数:7
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