links), sulphide (sulphur glycosidic links) and carbon to carbon links
(carbon glycosidic links) are known (Figure 1.17). Each type of glycosidic
link will exhibit the characteristics of the structure forming the link.
For example, oxygen glycosidic links are effectively acetals and so undergo
hydrolysis in aqueous solution. Both trivial and systematic nomenclature
is used for glycosides (Figure 1.17). In systematic nomenclature the radical
name of the aglycone preceeds the name of the glycone, which has the
suffix-oside.
N
N
N N
NH 2
O
H
OHOH
H
CH 2
H
HO P O P O P O
OH OH OH
OOO
H
CH 2 OH
OH
O
OH
O
HO
CH 2 OH
H
OH
H
H
OH
H
O NH
HO
SO 2 NH 2
CH 2 OH
H
OH
H
H
OH
H
O
HO
OCH 3
CH 2 OH
H
OH
H
H
OH
H
Methylβ-D-glucoside
4 1
N 4 -(β-D-Glucopyranosyl)sulphanilamide
(a)
(b)
5-(β-D-Ribofuranosyl)uracil
5
H
H O
H
NH
O
HN
OH
HOCH 2 O
H
OH
1
O O C
CN
HO
CH 2 OH
H
OH H
H
H
OH
H
Prunasin, ex wild cherry bark
H
OCH 2 CH 3
H
H
H
HOCH (^2) O
H
OH
Ethylβ-D-deoxyriboside
Adenosine triphosphate (ATP), ex mammals
Aloin, ex aloes
(c)
Figure 1.17 Examples of (a) oxygen glycosides, (b) nitrogen glycosides and (c) carbon glycosides.
The shaded parts of the structures are the aglycone sections
Glycoproteins are glycosides that have a protein aglycone. The protein is
usually linked to a polysacharide (See section 1.4.4) by an O or N glycosidic
link. Glycoproteins are found in all forms of life. They exhibit a wide range of
biological activities. For example, they may act as receptors, hormones and
enzymes.
16 BIOLOGICAL MOLECULES