PMID- 20565134
OWN - NLM
STAT- MEDLINE
DCOM- 20100823
LR  - 20131121
IS  - 1520-4995 (Electronic)
IS  - 0006-2960 (Linking)
VI  - 49
IP  - 29
DP  - 2010 Jul 27
TI  - Functional switching of Amphitrite ornata dehaloperoxidase from O2-binding globin 
      to peroxidase enzyme facilitated by halophenol substrate and H2O2.
PG  - 6064-9
LID - 10.1021/bi100741z [doi]
AB  - Amphitrite ornata dehaloperoxidase (DHP) is the first heme-containing globin 
      possessing a native peroxidase enzymatic activity. DHP catalyzes the 
      H(2)O(2)-dependent dehalogenation of halophenols. By possessing this detoxifying 
      enzymatic activity, these organisms are able to thrive in an environment 
      contaminated with toxic haloaromatics. It has been proposed that DHP evolved from 
      a dioxygen carrier globin protein and therefore possesses dual physiological 
      roles of O(2) carrier and dehaloperoxidase. Although DHP is isolated in the 
      catalytically inactive oxyferrous state (oxy-DHP), we find that the combination 
      of H(2)O(2) and the substrate 2,4,6-trichlorophenol (TCP) brings about facile 
      switching of oxy-DHP to the enzymatically active ferric state via a process 
      likely involving substrate radicals (TCP*). In contrast, in the absence of TCP, 
      H(2)O(2) alone converts oxy-DHP to an inactive state (compound RH) instead of 
      oxidizing the enzyme to the ferric state. Further, although the rate of 
      autoxidation of oxy-DHP is somewhat enhanced by the presence of TCP, the effect 
      is too small to be the functional switch. Instead, both substrate and H(2)O(2) 
      are needed to convert oxy-DHP to the catalytically active ferric state. These 
      observations provide a physiological link between the O(2) carrier role of the 
      ferrous protein and the peroxidase activity of the ferric enzyme in this 
      bifunctional protein.
FAU - Du, Jing
AU  - Du J
AD  - Department of Chemistry and Biochemistry, University of South Carolina, Columbia, 
      South Carolina 20208, USA.
FAU - Sono, Masanori
AU  - Sono M
FAU - Dawson, John H
AU  - Dawson JH
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Chlorophenols)
RN  - 0 (Halogens)
RN  - 0 (Hemoglobins)
RN  - 42VZT0U6YR (Heme)
RN  - 9004-22-2 (Globins)
RN  - BBX060AN9V (Hydrogen Peroxide)
RN  - EC 1.11.1.- (DHP I dehaloperoxidase)
RN  - EC 1.11.1.- (Peroxidases)
RN  - MHS8C5BAUZ (2,4,6-trichlorophenol)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Animals
MH  - Chlorophenols/*chemistry
MH  - Chromatography
MH  - Enzyme Activation
MH  - Globins/*chemistry
MH  - Halogens/chemistry
MH  - Heme/chemistry
MH  - Hemoglobins/*chemistry
MH  - Hydrogen Peroxide/*chemistry
MH  - Oxidation-Reduction
MH  - Oxygen/*chemistry
MH  - Peroxidases/*chemistry
MH  - Polychaeta/*enzymology
EDAT- 2010/06/23 06:00
MHDA- 2010/08/24 06:00
CRDT- 2010/06/23 06:00
PHST- 2010/06/23 06:00 [entrez]
PHST- 2010/06/23 06:00 [pubmed]
PHST- 2010/08/24 06:00 [medline]
AID - 10.1021/bi100741z [doi]
PST - ppublish
SO  - Biochemistry. 2010 Jul 27;49(29):6064-9. doi: 10.1021/bi100741z.