Fatty Acids and Glycerides

481 Pages·1978·15.52 MB·English

by  Arnis Kuksis (auth.)

1
Handbook of
Lipid Research
Fatty Acids and
Glycerides
Handbook of Lipid Research
Editor: Donald J. Hanahan
The University of Texas Health Center at San Antonio
San Antonio, Texas
Volume 1 Fatty Acids and Glycerides
Edited by Arnis Kuksis
Volume 2 The Fat-Soluble Vitamins
Edited by Hector F. DeLuca
if
Handboo
Lipid Research
Fatty Acids and
Glycerides
Edited by
Arnis Kuksis
Banting and Best Department of Medical Research
University of Toronto
Toronto, Ontario, Canada
Plenum Press · New lVrk and London
Library of Congress Cataloging in Publication Data
Main entry under title:
Fatty acids and glycerides.
(Handbook of lipid research; v. 1)
Includes bibliographies and index.
1.. Acids, Fatty. 2. Glycerides. I. Kuksis, Amis. II. Series. [DNLM: 1. Lipids.
QU85 H236) QP751.H33 vol. I [QP752.F351 574.1'9247s
[574.1'92471 77-25277
ISBN-13:978-1-4684-2567-3 e-ISBN-13:978-1-4684-2565-9
DOl: 10.1007/978-1-4684-2565-9
© 1978 Plenum Press, New York
A Division of Plenum Publishing Corporation
227 West 17th Street, New York, N.Y. 10011
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted,
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
Contributors
w.
Carl Breckenridge, Departments of Clinical Biochemistry and Medicine,
University of Toronto, Toronto, Ontario, MSS 21S, Canada
Dmytl'O Buchnea, Banting and Best Department of Medical Research, University of
Toronto, Toronto, Ontario, MSG lL6, Canada
Edward A. Emlce", Northern Regional Research Center Agricultural Research
Service, U.S. Department of Agriculture, Peoria, Illinois 61604
John L. he'l'son, Division of Nutrition, Food and Drug Administration, Washington,
D.C. 20204
A,.,. Kubis, Banting and Best Department of Medical Research, University of
Toronto, Toronto, Ontario, MSG lL6, Canada
John J. My/Ier, Banting and Best Department of Medical Research, University of
Toronto, Toronto, Ontario, MSG lL6, Canada
Patrick J. A. O'Doherty, G. F. Strong Laboratory, Department of Medicine, The
University of British Columbia, Vancouver, British Columbia, VSZ IM9,
Canada
AIII1I J. Slrq]lll1'd, Division of Nutrition, Food and Drug Administration,
Washington, D.C. 20204
John L. WeiIIrauch, Consumer and Food Economics Institute, Agricultural
Research Service, U.S. Department of Agriculture, Hyattsville, Maryland
20782
Foreword
The advances in lipid biochemistry over the past 25 to 30 years have been dramatic
and exciting. The elucidation of the pathways of fatty acid biosynthesis and
oxidation, the delineation of the biogenesis of cholesterol from small-molecular
weight precursors, the structure proof of simple and complex lipids from plants,
animals, and microorganisms, are excellent examples of the spectacular advances
made during the golden era of lipid biochemistry. The multifaceted discoveries in
these diverse areas of study could be attributed to development of highly
sophisticated column chromatographic techniques for separation and purification of
simple and complex lipids. The advent of thin-layer chromatography as well as gas
liquid chromatography provided an explosive impetus to research developments in
this field. Concomitant advances in mass spectrometry allowed an interface with
gas-liquid chromatography which spawned even greater insight into the structure of
lipids. These eventful days of lipid chemistry nearly 25 years ago led to a relatively
quiescent period wherein scientists applied these newly available techniques to
investigation of the behavior of isolated (lipid) enzyme systems and to unraveling the
intricacies of the metabolic behavior of lipids in the intact cell or whole organisms.
Then, in the early 1960s, a decided change in research emphasis developed with
the advent of a simple, reproducible procedure for the isolation of cell membranes.
There can be little challenge to the fact that the ready availability of the hemoglobin
free mammalian erythrocyte membrane was an enormous stimulus to investigators
interested in the biochemical characteristics of lipids in these structures. In the
ensuing years there has been an exponential rise in studies on membrane structure
with considerable attention focused initially on the lipids, which was followed later by
excellent studies on the membrane proteins. While this has been a provocative era, it
had become increasingly apparent that there was developing a generation of
investigators whose background in lipid chemistry and biochemistry was limited.
This was understandable in part since many of these scientists had come through the
halcyon days of RNA-DNA during which such "mundane" topics as lipids were of
minor consideration in the graduate sequence in many departments and laboratories.
Certainly, molecular biology had made its mark. This trend was of great concern
since there was a limited number of books on lipid chemistry available to persons
potentially interested in this topic.
Hence, it was decided to undertake a systematically conceived series of books
entitled Handbook of Lipid Research. The plan was to have each volume in this
series edited by an expert (or experts) in the particular area of interest. The topics for
consideration in this series would range from fatty acids and glycerides,
rii
Foreword
phospholipids, sphingolipids to the sterols and steroids, lipid vitamins, and then to
the more biological facets of lipids. In order to have this undertaking flourish, it was
mandatory that experts in the field of lipid chemistry and biochemistry be invited to
contribute. In addition, it was our intention to have each of the individual volumes
devoted wherever possible to the chemical and/or biochemical aspects of a particular
subject. The basic concept was not to achieve an encyclopedic compendium but
rather foster a tightly structured reference text of a reasonable length. Thus, each
volume would reflect the individual editor's (or editors') thoughts, ideas, and insights
into their area of expertise. As a reference source, these volumes should appeal and
be helpful to graduate students, postdoctoral students, investigators who wish a
"refresher" in a particular area, and novices in related fields. Even the seasoned
investigator should find these books of considerable usefulness. These books will
make evident the fact that tremendous progress has been made in lipid biochemistry
to date and that the exciting years ahead, in which the structure of the membrane will
be forthcoming, depend on a basic understanding of the chemical behavior of lipids.
Donald J. Hanahan
San Antonio
Preface
Fatty acids and acylglycerols are the basic constituents of natural fats where they
occur in the free form and as components of complex lipids. The universal
distribution and industrial importance of these compounds aroused much early
interest in their composition and physicochemical properties, but their bio
chemical significance was largely dismissed as that of an energy source. The
introduction of modern methods of separation and determination of structure of fatty
acids and acylglycerols over the past two decades has revealed a great complexity in
the composition of natural fats and has led to the recognition that, in addition to
providing energy, fatty substances serve a number of other metabolic and
physiological functions. Although a wide variety of lipid structures may be
compatible with the survival of a biological system, there is good reason to believe
that the optimal composition and structure of the fatty acids and acylglycerols of
animal species and tissues are genetically controlled.
As a result of this change in the emphasis of the biological role of lipids, special
methodology, including isotope dilution and enantiomeric probing, has been
developed to deal with the more detailed features of the fatty acid and acylglycerol
molecules required for metabolic studies. This volume summarizes current
methodology and specific findings in the area of fatty acid and acylglycerol
separation, determination of structure and chemical synthesis, along with appropri
ate tabulations of results and a complete documentation of sources. Chapter 1
describes the specific methodology used and the separations obtained for most
classes of natural and synthetic fatty acids. It includes an extensive collection of
equivalent chain-length values for the fatty acid methyl esters obtained by gas-liquid
chromatography with the more common liquid phases. Chapters 7 and 8 tabulate the
fatty acid composition of selected dietary fats and animal tissues and provide a
critical commentary on the interpretation of these data from the points of collection
of representative samples and preparation and quantitation of fatty acids. Chapter 2
describes the synthesis and determination of structure of isotope-labeled fatty acids,
while Chapter 5 describes the synthesis and proof of structure of enantiomeric acyl
glycerols containing both natural and isotope-labeled acids. These chapters contain
extensive tabulations of synthetic fatty acids (Chapter 2) and acylglycerols (Chapter
5). Both radioactive- and stable-isotope-Iabeled fatty acids and acylglycerols have
been extensively employed in metabolic studies, as discussed in Chapter 6, along
with appropriate listing of specific applications and general routines. Chapters 3 and
4 cover the separation and determination of structure of natural acylglycerols and
contain a wealth of tabulated data on the chromatographic behavior of different
JC
acylglycerols and on the stereochemical structure of natural triacylglycerols,
respectively. The various experimental routines are critically appraised, and specific
recommendations for improved analyses are made.
All the contributors have themselves done valuable research in the fatty acid
and glycerolipid field, and several of them give ·personal accounts of their work that
would not appear in an ordinary scientific paper. While the discussion has been
oriented primarily toward persons engaged in lipid research, the detailed account of
the analytical behavior and composition of naturaI and synthetic fatty acids and
acylglycerols provides a unique compendium of knowledge, which should serve as an
important reference to workers in related areas, and hasten progress in the
understanding of the role of fatty acids and acylglycerols in biochemical and
metabolic transformations and in cellular structure.
I express my thanks to the various authors for the excellent coverage and
critical review of the material assigned. A special debt of gratitude is owed to Dr. D.
J. Hanahan for advice in the selection of the topics and for a constructive criticism of
the individual contributions.
Arnis Kuksis
Toronto
Contents
Chapter 1
Separation and Determination of Structure ofF atty A.cids
Amis Kubis
1.1. Introduction 1
1.2. Preparation and Isolation of Fatty Acids 2
1.2.1. Generation of Free Acids . 2
1.2.2. Preparation of Derivatives 4
1.2.3. Transesterification of Bound Acids 6
1.3. Preliminary Fractionation of Fatty Acids 7
1.3.1. Conventional TLC 7
1.3.2. Argentation TLC 9
1.3.3. Other Methods 11
1.4. Identification of Fatty Acids by Gas-Liquid
Chromatography . 12
1.4.1. Short-Chain Acids 13
1.4.2. Saturated Normal-and Branched-Chain
and Cyclic Acids 14
1.4.3. Ethylenic Acids 21
1.4.4. Acetylenic Acids 30
1.4.5. Oxygenated Acids 36
1.5. Identification of Fatty Acids by Gas
Chromatography/Mass Spectrometry 40
1.5.1. Saturated Normal-and Branched-Chain
and Cyclic Acids 40
1.5.2. Ethylenic and Acetylenic Acids. 43
1.5.3. Oxygenated Acids 45
U.4. Stable Isotope-Labeled Fatty Acids 48
1.6. Ancillary Methods of Fatty Acid Identification 50
1.6.1. Chemical Methods 50
1.6.2. Spectrometric Methods 53
1.6.3. Enzymatic Methods . 61
1.7. Summary and Conclusions 64
1.8. References 66