PMID- 10580095
OWN - NLM
STAT- MEDLINE
DCOM- 20000113
LR  - 20190621
IS  - 0014-5793 (Print)
IS  - 0014-5793 (Linking)
VI  - 462
IP  - 1-2
DP  - 1999 Nov 26
TI  - Activation volumes for intramolecular electron transfer in bovine heart 
      cytochrome c oxidase.
PG  - 75-8
AB  - The present work examines the activation volumes associated with intramolecular 
      electron transfer (ET) within the CO-mixed-valence form of bovine heart 
      cytochrome c oxidase (CcO). Activation volumes for intramolecular ET between 
      cytochrome a(3) and cytochrome a (k=(6. 7+/-0.9)x10(5) s(-1) at ambient pressure) 
      and between cytochrome a and Cu(A) (k=(5.9+/-1.7)x10(4) s(-1)) are found to be 
      +41+/-5 ml/mol and +28+/-4 ml/mol, respectively. Examination of the crystal 
      structures of both the fully oxidized and fully reduced forms of bovine heart CcO 
      suggest that the activation volume for the ET between cytochrome a(3) and 
      cytochrome a arises from structural changes localized at cytochrome a(3) upon 
      heme reduction. Similarly, the activation volume for the ET between cytochrome a 
      and Cu(A) is primarily due to structural changes localized at Cu(A) upon 
      reduction of this site. Reduction/oxidation of cytochrome a does not appear to 
      make any significant contribution to the activation volume. Overall, these 
      results suggest conformational regulation of ET by both Cu(A) and cytochrome a(3) 
      but not cytochrome a.
FAU - Larsen, R W
AU  - Larsen RW
AD  - Department of Chemistry, University of Hawaii at Manoa, 2545 The Mall, Honolulu, 
      HI 96822, USA. rlarsen@gold.chem.hawaii.edu
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - England
TA  - FEBS Lett
JT  - FEBS letters
JID - 0155157
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Animals
MH  - Cattle
MH  - Electron Transport
MH  - Electron Transport Complex IV/chemistry/*metabolism
MH  - Enzyme Activation
MH  - Myocardium/*enzymology
MH  - Oxidation-Reduction
MH  - Protein Conformation
EDAT- 1999/12/02 00:00
MHDA- 1999/12/02 00:01
CRDT- 1999/12/02 00:00
PHST- 1999/12/02 00:00 [pubmed]
PHST- 1999/12/02 00:01 [medline]
PHST- 1999/12/02 00:00 [entrez]
AID - S0014-5793(99)01517-3 [pii]
AID - 10.1016/s0014-5793(99)01517-3 [doi]
PST - ppublish
SO  - FEBS Lett. 1999 Nov 26;462(1-2):75-8. doi: 10.1016/s0014-5793(99)01517-3.