Carbohydrate Analysis
255
Tab. 2
(
continued
)
Enzyme
commission
(EC) number
Common name
Usual source
Useful speciFcity
a
3.2.1.41
Pullulanase
A. aerogenes
Internal Glc(
α
1
6)-Glc in
predominantly
α
1
4g
lucans
3.2.1.45
Ceramide glycanase
Leech
Glucosyl
β
-1,4-linkages in neutral
glycosylceramides
3.2.1.51
α
-Fucosidase
Beef kidney
Terminal
α
-linked fucose in glycans
3.2.1.96
Endoglycosidase D
D. pneumoniae
Chitobiose in high-mannose (Man
5
)
glycoproteins
3.2.1.96
Endoglycosidase F
Flavobacterium
meningosepticum
Chitobiose in high-mannose, hybrid,
and biantennary glycoproteins
3.2.1.96
Endoglycosidase H
Streptomyces
plicatus
Chitobiose in high-mannose and
hybrid glycoproteins
3.2.1.97
O
-Glycosidase
D. pneumoniae
Linkage of Gal(
β
1
3)GalNAc to
Ser/Thr in glycoproteins
3.2.1.103
Endo-
β
-galactosidase
Bacteroides fragilis
Internal galactose
β
1,4-linked to
GlcNAc in polylactosamines
3.2.2.18
N
-Glycosidase F
F. meningosepticum
Linkage of
N
-glycans to Asn in
glycoproteins
Lyases
Cleavage of
4.2.2.4
Chondroitinase
Proteus vulgaris
Chondroitin sulfate/dermatan
sulfate from proteoglycans
Isomerases
Isomerization of
5.3.1.9
Phosphoglucose
isomerase
S. cerevisiae
Glucose-6-phosphate
a
For abbreviations, see Fig. 1.
after the material has totally reacted. To
produce the change in absorption or to
pull the reaction in the required direction,
several coupled enzymatic reactions are
often required.
Enzymes
are
also
used
in
biosen-
sor
s–analytical devices that convert biolog-
ical responses directly to electrical signals.
A number of such devices are commer-
cially available. The most widespread is
the glucose biosensor, which utilizes the
reaction of glucose oxidase at the electrode
surface. The other major use of enzymes
is in the sequence and linkage analysis
of polysaccharides and glycoconjugates
(Table 2 and Fig. 2).
2.2
Chromatography
Given the wide variety of carbohydrates,
it is not surprising that there exists a
wide diversity of chromatographic meth-
ods for the separation of carbohydrates
(Table 3). They generally deliver quanti-
tative data where standards are available.
Positive con±rmation of the identity of
chromatographic peaks (e.g. by MS) may
be needed when the analysis involves
complex mixtures or if standards are not
available. HPLC and HPAEC are the most
common
methods
of
chromatographic
analysis, with GC still used sometimes for
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