An EPR study of the peroxyl radicals induced by hydrogen peroxide in the haem proteins | Health & Environmental Research Online (HERO)

HERO ID

6597506

Reference Type

Journal Article

Title

An EPR study of the peroxyl radicals induced by hydrogen peroxide in the haem proteins

Author(s)

Svistunenko, DA; ,

Year

2001

Is Peer Reviewed?

1

Journal

Biochimica et Biophysica Acta
ISSN: 0006-3002
EISSN: 1878-2434

Publisher

ELSEVIER SCIENCE BV

Location

AMSTERDAM

Volume

1546

Issue

2

Page Numbers

365-378

Language

English

PMID

11295442

DOI

10.1016/s0167-4838(01)00157-1

Web of Science Id

WOS:000168210300011

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035820321&doi=10.1016%2fS0167-4838%2801%2900157-1&partnerID=40&md5=68064cc41c6a37d0b95ef0269797f0c3
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Abstract

The reaction of hydrogen peroxide H(2)O(2) with horse heart metmyoglobin (HH metMb), sperm whale metmyoglobin (SW metMb) and human metHb (metHbA) was studied at pH 6-8 by low temperature (10 K) EPR spectroscopy with the emphasis on the peroxyl radicals formed during the reaction. The same type of peroxyl radical was found in both myoglobin systems, as was concluded from close similarities in the spectroscopic properties of the radicals and in their kinetic dependences. This is consistent with previous reports of the peroxyl radical being localised on the Trp14 of SW and HH myoglobins. There are two types of peroxyl radical found in the metHbA/H(2)O(2) system, one (ROO-I) having spectral parameters, kinetic and pH dependences similar to those of the peroxyl radical found in both myoglobin systems. The other peroxyl radical (ROO-II) found in metHbA treated with H(2)O(2) has slightly different, though distinguishable, spectral parameters and a significantly different kinetic dependence as compared to those of the peroxyl radical common for all three proteins studied (ROO-I). The concentration of ROO-I radical formed in the three proteins on addition of H(2)O(2) correlates with the effectiveness of incorporating molecular oxygen into styrene oxide reported before for these three proteins. It is shown that a different distance from Trp14 to haem iron in the three proteins might be the structural basis for the different yield of the peroxyl radical and the different efficiency of incorporation of molecular oxygen into styrene. The site of the peroxyl radical found only in metHbA (ROO-II) is speculated to be the Trp37 residue of the beta-subunit of HbA.

Keywords

haemoglobin; myoglobin; peroxide; electron paramagnetic resonance; tryptophan; peroxyl; radical