biochemistry of the fatty acids

399 Pages·2012·13 MB·English

BIOCHEMISTRY OF THE
FATTY ACIDS
AND THEIR COMPOUNDS, THE LIPIDS
By
W. R. BLOOR
Professor of Biochemistry and Pharmacology,
The University of Rochester,
Rochester, New York
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American Chemical Society
Monograph Series
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REINHOLD PUBLISHING CORPORATION
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COPYRIGHT, 1943, BY
REINHOLD PUBLISHING CORPORATION
All rights reserved
Second Printing
Primed in the United States of America by
THE CUINN CO., N. Y. C.
GENERAL INTRODUCTION
American Chemical Society Series of
Scientific and Technologic Monographs
By arrangement with the Interallied Conference of Pure and Applied
i Chemistry, which met in London and Brussels in July, 1919, the Ameri-
J can Chemical Society was to undertake the production and publication of
Scientific and Technologic monographs on chemical subjects. At the
same time it was agreed that the National Research Council, in coopera
tion with the American Chemical Society and the American Physical
Society, should undertake the production and publication of Critical
Tables of Chemical and Physical Constants. The American Chemical
Society and the National Research Council mutually agreed to care
for these two fields c;f Chemical development. The American Chemical
Society named as Trustees, to make the necessary arrangements for the
publication of the monographs, Charles L. Parsons, secretary of the
society, Washington, D. C; the late John E. Teeple, then treasurer of
the society, New York; and Professor Gellert Alleman of Swarthmore
College. The Trustees arranged for the publication of the A. C. S. series
of (a) Scientific and (b) Technologic Monographs by the Chemical Cata
log Company, Inc. (Reinhold Publishing Corporation, successors) of
New York.
The Council, acting through the Committee on National Policy of the
American Chemical Society, appointed editors (the present list of whom
appears at the close of this introduction) to have charge of securing
authors, and of considering critically the manuscripts submitted. The
editors endeavor to select topics of current interest, and authors recog
nized as authorities in their respective fields.
The development of knowledge in all branches of science, especially in
chemistry, has been so rapid during the last fifty years, and the fields
covered by this development so varied that it is difficult for any indi
vidual to keep in touch with progress in branches of science outside his
own specialty. In spite of the facilities for the examination of the litera
ture given by Chemical Abstracts and by such compendia as Beilstein's
Handbuch der Organischen Chemie, Richter's Lexikon, Ostwald's Lehr-
buch der Allgemeinen Chemie, Abegg's and Gmelin-Kraut's Handbuch
der Anorganischen Chemie, Moissan's TraTte de Chimie Minerale Gen-
erale. Friend's and Mellor's Textbooks of Inorganic Chemistry and Heil-
bron's Dictionary of Organic Compounds, it often takes a great deal of
time to coordinate the knowledge on a given topic. Consequently when
men who have spent years in the study of important subjects are willing
iv BIOCHEMISTRY OF THE FATTY ACIDS
to coordinate their knowledge and present it in concise, readable form,
they perform a service of the highest value. It was with a clear recog
nition of the usefulness of such work that the American Chemical Society
undertook to sponsor the publication of the two series of monographs.
Two distinct purposes are served by these monographs: the first,
whose fulfi.llment probably renders to chemists in general the most impor
tant service, is to present the knowledge available upon the chosen topic
in a form intelligible to those whose activities may be along a wholly dif
ferent line. Many chemists fail to realize how closely their investigations
may be connected with other work which on the surface appears far afield
from their own. These monographs enable such men to form closer con
tact with work in other lines of research. The second purpose is to pro
mote research in the branch of science covered by the monograph, by fur
nishing a well-digested survey of the progress already made, and by
pointing out directions in which investigation needs to be extended. To
facilitate the attainment of this purpose, extended references to the lit
erature enable anyone interested to follow up the subject in more detail. •
If the literature is so voluminous that a complete bibliography is imprac
ticable, a critical selection is made of those papers which are most
important.
AMERICAN CHEMICAL SOCIETY
BOARD OF EDITOHS
F. W. WiLLAKD, Editor of Monogra-phs.
Scientific Series:— Technologic Series:—
S. C. LiND, WALTER A. SCHMIDT,
W. MANSFIELD CLAUK, E. R. WEIDLEIN,
LINUS C. PAULING, W. G. WHITMAN,
L. F. FIESER. C. H. MATHEWSON,
THOMAS H. CHILTON,
BRUCE K. BROWN,
W. T. READ,
CHARLES ALLEN THOMAS
Preface
Proteins, carbohydrates and fats constitute the great groups of organic
food substane£S» Of these, the proteins and carbohydrates have received"
much attention from biochemists, while the fats, or more specifically the
. fatty acids'and their-cCSipounds, are only now passing through a similar
' stage of development.
In view of the increasing interest in these substances, which are now
recognized as taking a part in living structures and processes second only
to the proteins, it is desirable to gather together and evaluate the reported
material so that.it may serve as a background for future effort. The
following is an attempt in this direction. A clear pictme of the various
aspects of the field is not possible at the present time, but it is hoped that
what is presented will make such a picture possible as the new facts
appear.
The bibliography has presented the usual difficulty. Limits of space
prohibit the listing of all or even the more significant publications. What
is given is a list of those articles which either contribute most to the
general discussion or contain references which lead the interested reader
to other material not specifically mentioned.
W. R. BLOOB.
Rochester, N. Y.
April 15, 1943.

Contents
GENtaiAL INTRODUCTION iii
PREFACE v
CHAPTER I. CHEMISTRY: DESCRIPTIVE AND ANALYTICAL
Classification of the Lipids 1
Simple Lipids 3
Fats 3
Constitution 3
Physical Properties 4
Chemical properties 8
Synthesis 10
Waxes , 11
Compound Lipids 12
Phospholipids 12
Lecithin ^ 12
Cephahn 16
Lysolecithin and lysocephalin 17
Sphingomyelin 18
Phosphatidic acids 19
Glycolipids (galactolipids or cerebrosides) 19
Sulfolipids 20
Derived Lipids 21
Fatty acids 21
Occurrence 21
Saturated acids 21
Unsaturated acids 21
Properties of the fatty acids 25
Alcohols in natural combination with the fatty acids 30
Glycerol [CA(OH),] 30
Straight-chain alcohols '. 31
The sterols 31
Cholesterol 32
Bases 35
Hydrocarbons 36
Split products 36
Physico-chemical Conceptions of the Lipids 36
Methods of Examination of Tissue Lipids 37
Macromethods 37
Discussion 37
Hydrolysis 38
Dehydration and extraction 38
Procedure 40
Phospholipids 42
Cholesterol 42
Cholesterol esters 43
Fats :, 43
Fatty acids 43
Micromethods 44
Illustrative procedure 45
Extraction , 45
Isolation 46
Discussion 49
vii
viii CONTENTS
CHAPTER II. DIUESTION AND ABSORPTION
Nutritional Availability of Fats 58
Factors influencing digestion and absorption 69
Melting point 59
Nature of the fatty acids 61
Temperature 61
Vitamins 62
Species variation 62
Lipid-splitting Enzymes 62
Lipases (Fat-splitting Enzymes) 66
Gastric lipase 66
Pancreatic lipase 67
Intestinal lipase 70 •
Plant lipase 70
Methods of measuring activity 72
Esterases (Ester-splitting Enzymes) 73
Origin 73
Occurrence • 74
Functions of esterases 77
Fat Digestion 78
Digestion in the Stomach 79
Factors in fat splitting 79
Absorption from the stomach 80
Intestinal Digestion 81
Passage from the stomach 81
Factors in intestinal digestion 82
Absorption of Fats 85
Form in which Fat Leaves the Intestine 85
Absorption of split products 85
Absorption of unchanged fat 87
ResjTithesis of Fat 91
Fat Transport 95
Transfer to the lacteals 95
The lymph in fat transport 97
Changes in Fat During Absorption 98
Passage of Fat Directly into the Circulation 1(X)
Parenteral Administration of Fat 103
Digestion and Absorption of Other Lipids 103
Phospholipids -. 103
Sterols 104
Cholesterol 104
Other sterols 108
CHAPTER III. LIPIDS OF THE BLOOD
Introduction 115
Blood as a tissue 115
Nature of the fatty substances of blood , 116
Blood lipid equilibrium: the postabsorptive state 118
Lipid level in the postabsorptive state ., ., 119
Factors affecting the lipid level 120
Normal Basal Levels of Blood Lipids 122
Avft^ge Values '. 122
Data on different species 122
Lipid "constants" 128
Normal Variations in Members of the Same Species 129
Normal Variations in the Same Individual 131
Human Blood 132
CONTENTS ix ,
Chances in the Postabsorplive Level Produced by Food 136
Efifect of Fat Absorption on the Blood Lipids 136
Effect on fat 136
Effect on cholesterol 137
Effect on phospholipid 139
Fat ingestion and the blood lipids in humans 140
Factors Modifying the Effect of Fat Absorption 141
Removal mechanism 141
Lipid destruction in the lungs 142
Nutritional state and diet 143
Intravenous Injections 144
Effect of Diet on the Blood Lipids 145
Variations in Blood Lipids in Normal Individuals 147
The Reproductive Cycle and the Blood Lipids 147
Age 151
Work 152
Effect of Abnormal Conditions on the Blood Lipids 153
Nutritional Abnormalities 153
Fasting '. 154
Anesthesia and narcosis 156
Anemia 158
Cancer 162
Vitamin deficiencies 163
Avitaminosis 163
Vitamin B deficiency 4 163
Scurvy 164
Vitamin A deficiency 164
Irradiation 164
Magnesium deficiency 164
Diabetes 164
Insulinization 167
Effect of various drugs 168
Phlorizin 168
Phosphorus 168
Hydrazine poisoning 169
Acids 169
Snake root or rich weed (Eupatorium verticaefolium) 169
Tartrates 169
Deposits of metabolic excesses 169
Muscular dystrephy 170
Fattening and* obesity 170
Epilepsy and water balance 170
Skin disorders • • • 171
Infections 172
Infections and immunity 172
Serological reactions 173
Tuberculosis 174
Leprosy ..' 175
Syphilis • 175
Mental Disease 175
Organic Diseases 175
Angina pectoris 175
, Arteriosclerosis and hypertension 175
Arthritis 177
Liver disease 177
Kidney disorders 179
Pancreatitis 181
Thyroid conditions 181
Hypophysis dysfunction 182
Operative procedures 182
X CONTENTS
Effect of the Lipids of the Blood on its Properties 183
Lipemia 183
Embolism 183
Hemolysis 183
CoaKulation 184
Sedimentation time of corpuscles 184
Physico-chemical relations 184
Combinations of the lipids with other substances in blood 185
Summary 186
Blood lipid composition in normal animals 186
Abnormal bodily states 187
CHAPTEE IV. THE LIPIDS IN TISSUE
Introduction 196
Data on Tissue Lipids 198
Muscle _ , 198
Normal variations 198
Muscle lipids under various abnormal conditions 202
Brain and nervous system 203
Liver 208
Kidney ; 219
Adrenal elands 219
Spleen * 221
Bone marrow 222
Reproductive organs 222
Skin and appendages 225
Gall bladder 228
Human fat 228
Cold-blooded animals , 228
Tissue Lipids in Abnormal Conditions 229
Diseases involving lipid deposits 231
Nature and Function of Tissue Lipids .. •. 236
Fat 236
Nature of stored fat 236
Effect of environmental temperature on nature of stored fat 240
Phospholipids and Sterols 244
Role as essential cellular constituents ..... 244
Fatty acids in combination in the phospholipids 252
Relation of lipid content to physiological activity 256
Lipids of Plants 257
Fat 257
Phospholipid 258
Unsaponifiable 260
Lipids of Microorganisms 263
Bacteria 264
Yeast .-. 273
Molds - 275
CHAPTER V. LIPID METABOLISM
Introduction 286
Physiological Synthesis of the Lipids 287
Synthesis of Neutral Fat 287
Synthesis of Sterols 291
Synthesis of Phospholipids 293
Intermediary Metabolism and the Role of the Liver 294
Fat Deposition and Mobilization 294
Mobilization and storage in the liver 294
Phospholipids of the liver in fat metabolism 300