The two unpaired electrons of oxygen spin in the same direction thus, oxygen is a biradical, but is not a very dangerous free radical. Through evolution, oxygen was chosen as the terminal electron acceptor for respiration. Free radicals are involved in: Enzyme-catalyzed reactions Electron transport in mitochondria Signal transduction and gene expression Activation of nuclear transcription factors Oxidative damage to molecules, cells, and tissues Antimicrobial action of neutrophils and macrophages Aging and disease Normal metabolism is dependent on oxygen, a free radical. Free radicals are generated during oxidative metabolism and energy production in the body. The odd, or unpaired, electron is highly reactive as it seeks to pair with another free electron. Free radicals are molecules with an odd number of electrons. However, the same free radicals that are generated during oxidative stress are produced during normal metabolism and thus are involved in both human health and disease.
Overwhelming evidence indicates that oxidative stress can lead to cell and tissue injury. Current printing (last digit): 10 9 8 7 6 5 4 3 2 1 PRINTED IN THE UNITED STATES OF AMERICA Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing from the publisher. For more information, write to Special Sales/Professional Marketing at the headquarters address above. 270 Madison Avenue, New York, NY 10016 tel: 21 fax: 21 Eastern Hemisphere Distribution Marcel Dekker AG Hutgasse 4, Postfach 812, CH-4001 Basel, Switzerland tel: 41-6 fax: 41-6 World Wide Web http:/ /The publisher offers discounts on this book when ordered in bulk quantities. ISBN: 0-8247-0530-0 This book is printed on acid-free paper.
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