Polysaccharides Peptides and Proteins. Pharmaceutical Monographs

205 Pages·1966·11.857 MB·English

by  R. T. Coutts, G. A. Smail and J. B. Stenlake (Auth.)

PHARMACEUTICAL MONOGRAPHS
GENERAL EDITOR
J. B. STENLAKE, D.SC,Ph.D.,F.P.S.,F.R.I.C,F.R.S.E.
Professor of Pharmacy, University of Strathclyde
Volume 4
POLYSACCHARIDES,
PEPTIDES AND PROTEINS
Already published
Volume 1
AN INTRODUCTION TO MICROBIOLOGY
W. B. Hugo, B.Pharm., Ph.D.(Lond.), F.P.S.
Volume 2
AN INTRODUCTION TO PARASITOLOGY
John M. Watson, D.Sc.(Lond.), A.R.C.Sc.
Volume 3
STERILISATION AND DISINFECTION
T. D. Whittet, B.Sc, Ph.D., F.P.S., F.R.I.C, D.B.A.
W. B. Hugo, B.Pharm., Ph.D.(Lond.), F.P.S.
G. R. Wilkinson, F.P.S.
POLYSACCHARIDES
PEPTIDES AND
PROTEINS
BY
R. T. COUTTS B.Sc, Ph.D., A.R.C.S.T., M.P.S.
University of Saskatchewan, Saskatoon
G. A. SMAIL B.Sc, A.R.C.S.T., M.P.S.
University of Strathclyde
WILLIAM HEINEMANN MEDICAL BOOKS LTD
LONDON
First published 1966
© R. T. Coutts and G. A. Smail 1966
Printed in Great Britain by
Butler & Tanner Ltd, Frome and London
GENERAL PREFACE
The aim of this series of pharmaceutical monographs is to provide
an up-to-date series of short publications for teaching general and
specialised topics to undergraduate students of pharmacy and
allied subjects. Each monograph in the series is the work of an
expert or group of experts actively engaged in teaching or practice.
For convenience, however, groups of two or more monographs on
related subjects have been collected together for publication.
Each monograph is intended to serve as the basis for a group of
lectures or tutorials in the honours and pre-honours years of
undergraduate courses in pharmacy and allied subjects in British
and Commonwealth Universities and, of necessity, some mono­
graphs are slanted toward the more specific requirements of these
countries. We have, however, endeavoured to keep the mono­
graphs on a general plane to ensure their suitability for use in other
parts of the world.
An attempt has been made to present the subject matter of in­
dividual monographs in such detail that it provides a permanent
record for study purposes capable of being used by students in lieu
of lecture notes. Each monograph, however, sets out to provide not
merely a detailed account of essential subject matter, such as would
be required for examination purposes, but also seeks to indicate its
relevance and importance to pharmaceutical studies in general. In
this respect, monographs extend naturally to the boundaries of
knowledge in all major aspects, and wherever possible present
appropriate rival views and hypotheses in sufficient detail for the
student to grasp their essential detail without reference to the
original. The texts are, however, referenced to provide additional
sources of information.
I am indebted to the authors of the individual monographs for
their willingness to collaborate with me in the preparation of this
series. I should also like to express my thanks to my colleagues and
many friends for their help and advice in framing the series and for
discussions on individual monographs. I should further like to
express my sincere thanks to Mrs S. Cohen for invaluable secre­
tarial assistance.
J. B. S.
v
PREFACE TO VOLUME 4
A wide variety of naturally-occurring macromolecules which are
either polysaccharide, peptide or protein in nature are important
as medicinal and pharmaceutical agents. These include such widely
diverse materials as peptide hormones and antibiotics, immuno-
logical products, blood products, ligatures and sutures, surgical
dressings' materials, and also such materials as starches, gums and
mucilages, which are valuable as adjuncts to pharmaceutical
formulation.
Certain of these more specialised materials form the subject of
separate monographs to appear later in this series. The prepara­
tion, use and development of pharmaceutical products of this type,
which are of biological origin, depend on a better understanding
than has hitherto been considered necessary of their chemical make­
up, and of the relationship between their physical and chemical
properties and the corresponding properties of the biological and
pharmaceutical systems with which they interact in use. The pres­
ent volume is, therefore, confined to the consideration of the basic
chemical and physical properties of polysaccharides on the one
hand, and peptides and proteins on the other, exemplified by con­
sideration of the detailed structure of selected examples of homo­
geneous and simple heterogeneous materials of each class which
have important medical and pharmaceutical uses. An attempt has
been made wherever possible to relate their properties, especially
physical properties, to their pharmaceutical use.
J. B. S.
vii
ACKNOWLEDGMENTS
(Amino acids and proteins)
Figure 3 page 114
Taken from S. Moore, D. H. Spademan and W. H. Stein (1958), Analyt.
Chem., 30, 1186.
Figure 4 page 117
Taken from R. B. Corey and L. Pauling (1953), Proc. Roy. Soc, 141B, 17.
Figure 5 page 119
Taken from K. U. Linderstr0m-Lang and J. A. Schellman (1959), Protein
Structure and Enzyme Activity in The Enzymes, Vol. I, edited by P. D.
Boyer, H. Lardy, and K. Myrback, Academic Press, New York, p. 448.
Figure 6 page 119
Taken from C. O. Wilson and O. Gisvold (1962), Textbook of Organic,
Medicinal and Pharmaceutical Chemistry, 4th Ed., Pitman Medical Pub­
lishing Co. Ltd., London, p. 737.
Figure 7 page 121
Taken slightly modified from H. N. Rydon (1962), Péptide Synthesis, Royal
Institute of Chemistry, Lecture Series No. 5.
Tables 8 9, 10 pages 129, 130,
9
Taken from V. du Vigneaud, C Ressler and S. Trippett (1953), /. Biol.
Chem., 205, 949 et seq.
Figure 8 page 128
J. A. Pierce and V. du Vigneaud (1950), /. Biol. Chem., 182, 362.
Table 16 page 163
Taken from A. B. Lerner and T. H. Lee (1962), Vitamins and Hormones,
20, 342.
Table 17 page 167
Taken from K. Hofman (1962), Ann. Rev. Biochem., 31, 228.
Figure 14 page 178
Taken from K. Hallas-Moller, K. Petersen and J. Schlichtkrull (1952),
Science, 116, 394.
Figure 15 page 181
Taken from F. B. Peck (1956), cited by J. C. Krantz and C. J. Carr (1961)
The Pharmacological Principles of Medical Practice, 5th Ed., Balliere,
Tindall and Cox, London, p. 1312.
77
CHAPTER 1
INTRODUCTION
Many substances of pharmaceutical importance belong to the
class of compounds known as polysaccharides. Such compounds
are derived by multiple combination of simple sugars which, to­
gether with the polysaccharides, are collectively termed carbo­
hydrates. The term carbohydrate (hydrate of carbon) is obtained
from the empirical formula Cx(H 0)y, possessed by almost all
2
compounds of this class, though such a name is not descriptive of
their nature and, furthermore, not all compounds of such a formula
are carbohydrates. All carbohydrates are, however, polyhydroxy-
lated compounds, the majority of which contain 'free' or 'masked'
aldehydic or ketonic groups.
The simple carbohydrates are called sugars and are crystalline,
water-soluble substances with a sweet taste. Usually their names
end in the suffix '-ose'. Sugars are classified as monosaccharides
and oligosaccharides. Examples of the former containing from
three to eight carbon atoms are found in nature, but the most
common monosaccharides possess five or six carbon atoms. Mono­
saccharides cannot be hydrolysed into smaller units. Oligosac­
charides consist of disaccharides, trisaccharides and tetrasac-
charides which yield two, three or four monosaccharide units,
respectively, on hydrolysis. It has recently been suggested, how­
ever, that the term oligosaccharide should be reserved for sugars
containing not more than nine monosaccharide units.
Polysaccharides are more complex substances with high mole­
cular weights. They are not sweet, non-crystalline, and are usually
insoluble in water. They yield a large number of monosaccharide
units on hydrolysis.
MONOSACCHARIDES
Monosaccharides can be further classified. If they contain an
aldehydic group, they are termed aldoses; if they possess a ketonic
group, they are called ketoses. The number of carbon atoms in
the molecule is indicated by a Greek prefix; trioses, tetroses, pen-
toses and hexoses contain three, four, five and six carbon atoms
5
POLYSACCHARIDES, PEPTIDES AND PROTEINS
respectively. Thus, a monosaccharide which has five carbon atoms
and possesses an aldehydic group is referred to as an aldopentose;
similarly a ketohexose is a monosaccharide with six carbon atoms,
containing a ketonic group. All monosaccharides are reducing
sugars because of their aldehydic or a-hydroxy ketonic groups, and
will reduce Fehling's Solution and Tollen's Reagent. The most im­
portant monosaccharides are the pentoses and hexoses.
Structure
Initially it is convenient to consider the aldohexoses as being
straight-chain pentahydroxyaldehydes. Such structures are in
agreement with their chemical properties, some of which are illus­
trated below:
NH OH —> oxime
2
CHO
I
—PhNHNH —> phenylhydrazone —> osazone
CHOH 2
I Ac 0 —> penta-acetate
2
CHOH
I Br /H 0-> HOOC(CHOH) CH OH
2 2 4 2
CHOH —
HNO3 -> HOOC(CHOH) COOH
I 4
CHOH
Na/Hg-> HOH C(CHOH) CH OH
I 2 4 2
CH2OH HI/P—> CH3CHI(CH2)3CH3 + CH3(CH2)4CH3
For similar reasons, the structure of the aldopentoses has been
proved to be CHO-(CHOH) CH OH. The only important ketose
3 2
is D-(—)-fructose. It, too, forms an oxime and a penta-acetate, and
on reduction yields a hexahydroxyalcohol (racemic mixture). Nitric
acid oxidation converts fructose into a mixture of trihydroxyglu-
taric, tartaric and glycollic acids, all of which contain less than six
carbon atoms and hence indicate that the carbonyl group in fruc­
tose is a ketonic one. Fructose has been established as a 2-keto-
hexose by the following sequence of reactions :
CH OH CH OH CH
2 2 3
OH I
I 1. HCN HI
c=o >>c< -> CH-COOH
heat
I 2. Hydrolysis | \COOH (CH2)3
(CHOH)3 (CHOH)3 I
CH2OH CH2OH CH3
fructose a-Methylcaproic acid
(racemate)
INTRODUCTION
Stereoisomerism
As the formula for an aldose,
CHO CHOHCHOHCHOHCHOH CHOH
2
possesses four asymmetric carbon atoms (marked *) it follows that
there are sixteen different configurations for the molecule of which
eight (D-forms) will be mirror images of the other eight (L-forms).
For similar reasons, there will be four D-forms and four L-forms
for the aldopentoses and the ketohexoses. Emil Fischer's contribu­
tion to the elucidation of these configurations earned him the
Nobel Prize in 1902.
Relative configuration. The triose, glyceraldehyde, has one asym­
metric carbon atom and, therefore, exists in two forms (enantio-
morphs I and II). Rosanoff (1906) proposed that dextrarotatory
glyceraldehyde should be represented as in (III) and this structure
is accepted as the arbitrary standard for D-sugars. Any sugar
which can be prepared from or converted into D(+)-glyceralde-
CHO CHO CHO CHO
1 1
1 1
H——OH HO—|—H
c^CH OH
2 C / C \ 2
H OH HO H CH2OH CH2OH
(I) (II) (HI) (IV)
hyde will belong to the D-series. Structure (IV) is the planar for­
mula of L-(— )-glyceraldehyde, the arbitrary standard for the
L-sugars. It is important to note that in the nomenclature of the
sugars, the positive and negative signs, previously written d and /
respectively, refer to the direction in which the monosaccharides
[—C—OH HO—C—H H—C—OH HO—C—H
1 1 1 1
CH OH CH OH CH CH
2 2 3 3
D-series L-series D-series L-series
rotate polarised light, and not to their configuration. Other sugars,
such as those which do not possess a hydroxymethyl group, are
still designated as D or L on the basis of the configuration about
the lowest asymmetric carbon atom in the chain.
The relationship of D-glyceraldehyde to other D-sugars can be
demonstrated by various means. Nitric acid oxidation of D-(—)-
7
POLYSACCHARIDES, PEPTIDES AND PROTEINS
erythrose, for example, gives mesotartaric acid while (—)-tartaric
acid is the product obtained from D-(+)-threose. As the configura-
CHO COOH CHO COOH
I j
H—!—OH H—i—OH HO- -H HO- -H
H— —OH H— -OH H- —OH H- -OH
CH OH COOH CH OH COOH
2 2
D-(—)-Erythrose Mesotartaric D-(+)-Threose L-(-)-Tartaric
acid acid
tions of the products are known, the configurations of the tetroses
are established. A method of ascending the sugar series, the Kiliani
Reaction, is a valuable way of determining the relative configura­
tion of an aldopentose or an aldohexose. Thus, when D-( +)-threose
is treated with hydrocyanic acid, a mixture of cyanhydrins is
CN CN
I I
CHO HCOH HOCH
I I I
HOCH -+ HOCH -1- HOCH
I I I
HCOH HCOH HCOH
I I I
CH,OH CH,OH
\ LCH20H
COOH co
To COOH
I I I
HCOH -~ HCOH HOCH HOCH
I I I I I
HOCH 0 t HOCH HOCH -+
I I I
I
HC HCOH HCOH
I I I
CHZOH CH,OH CH,OH
1 1
CV) (VI)
CHO COOH COOH CHO
I I I I
HCOH HCOH HOCH HOCH
I I I I
HOCH + HOCH HOCH t. HOCH
I I I I
HCOH HCOH HCOH HCOH
I I I I
CHzOH COOH COOH CH20H
Cvm
( W (IX) 6
8