Biology Reference
In-Depth Information
OH
O
O
O
O
HO
HO
HO
HO
HO
OH
+
NH
O
OH
OH
OH
HO
HO
O
HO
O
HO
H
O
P
O
2
O
O
Glc
4
GlcNF-1-P
phosphorylase
OH
O
O
O
HO
HO
OH
+ inorganic phosphate
OH
NH
OH
HO
HO
O
HO
O
HO
H
3
O
N-formyl-
α
-glucosaminyl-(1
�
4)-Glc
4
Figure 3.15
Phosphorylase-catalyzed
N
-formyl-
α
-glucosaminylation
of
Glc
using GlcNF-1-P.
4
in the phosphorylase-catalyzed glycosylation using GlcNF-1-P and
Glc
(5:1) was evaluated and compared with that using GlcN-1-P as
well as Glc-1-P under the same conditions. The total yields of the
glycosylated products were calculated on the basis of the amounts of
inorganic phosphate produced from the glycose 1-phosphates by the
phosphorylase catalysis. A reaction time of 4 days in the glycosylation
using GlcNF-1-P gave 33% yield of the products based on the amount
of Glc
4
, whereas the yield was 72% in the glycosylation using GlcN-
1-P. These data indicated that the phosphorylase recognized GlcN-
1-P more efficiently than GlcNF-1-P. However, the reaction using
Glc-1-P was much faster than such two reactions and yield reached
almost 100% in 45 min, because Glc-1-P is the native substrate for
phosphorylase catalysis.
4
α
-glucosaminylation
using GlcNF-1-P was also conducted in the presence of Glc
The
phosphorylase-catalyzed
N
-formyl-
or Glc
.
3
5
In the MALDI-TOF MS spectrum of the crude products using Glc
, no
peaks assignable to the molecular masses of oligosaccharides having
a GlcNF unit were observed, indicating no occurrence of
3
N
-formyl-
α
-
glucosaminylation of Glc
by GlcNF-1-P. Because the smallest glycosyl
acceptor for the phosphorylase-catalyzed glycosylation was Glc
3
,
4
Glc
was not recognized by phosphorylase. In the MALDI-TOF MS
spectrum of the crude products using Glc
3
, however, several peaks
5
separated by
m
/
z
equal to 162 were observed, which correspond to
