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2.4.1.1: glycogen phosphorylase

This is an abbreviated version!
For detailed information about glycogen phosphorylase, go to the full flat file.

Word Map on EC 2.4.1.1

Reaction

[(1->4)-alpha-D-glucosyl]n
+
phosphate
=
[(1->4)-alpha-D-glucosyl]n-1
 +
alpha-D-glucose 1-phosphate

Synonyms

1,4-alpha-glucan phosphorylase, alpha-1,4 glucan phosphorylase, alpha-1,4-glycan phosphorylase, alpha-glucan phosphorylase, alpha-glucan phosphorylase H, alpha-glucan/maltodextrin phosphorylase, alphaGP, amylopectin phosphorylase, amylophosphorylase, CcStP, cyosolic phosphorylase, GlgP, glucan phosphorylase, glucosan phosphorylase, glycogen phosphorylase, glycogen phosphorylase a, glycogen phosphorylase b, glycogen phosphorylase-a, GP, GP b, GPA, GPase, GPase a, GPb, GPBB, GPH, granulose phosphorylase, MalP, maltodextrin phosphorylase, More, muscle glycogen phosphorylase, muscle phosphorylase, muscle phosphorylase a and b, myophosphorylase, PF1535, Phb, PHO, Pho 2, Pho1, phosphorylase a, phosphorylase b, phosphorylase, alpha-glucan, plastidial phosphorylase, polyphosphorylase, potato phosphorylase, RMGPa, rmGPb, SP, starch phosphorylase, starch phosphorylase H, stGP, StP, tGPGG, type L alpha-glucan phosphorylase

ECTree

     2 Transferases
         2.4 Glycosyltransferases
             2.4.1 Hexosyltransferases
                2.4.1.1 glycogen phosphorylase

Engineering

Engineering on EC 2.4.1.1 - glycogen phosphorylase

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PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
H334A
-
site-directed mutagenesis, catalytic efficiency in the phosphorolysis reaction is similar to the wild-type enzyme, 50fold reduced binding of alpha-D-glucose 1-phosphate compared to the wild-type enzyme
H334G
purified H334G shows 0.05% and 1.3% of wild-type catalytic center activity for phosphorolysis of maltopentaose and substrate binding affinity in the ternary complex with enzyme bound to phosphate, respectively. Disruption of enzyme-substrate interactions in H334G is strictly local, affecting the protein environment of sugar carbon 6. pH profiles of the phosphorolysis rate for wild-type and H334G are both bell-shaped, with the broad pH range of optimum activity in the wild-type (pH 6.5-7.5) being narrowed and markedly shifted to lower pH values in the mutant (pH 6.5-7.0). External imidazole partly restores the activity lost in the mutant, without participating as an alternative nucleophile in the reaction
H334N
-
site-directed mutagenesis, 50fold reduced catalytic efficiency in the phosphorolysis reaction and highly reduced selectivity for alpha-D-glucose 1-phosphate, versus alpha-D-xylose 1-phosphate, in the synthesis reaction with 10fold reduced binding of alpha-D-glucose 1-phosphate compared to the wild-type enzyme
H334Q
-
site-directed mutagenesis, 150fold reduced catalytic efficiency in the phosphorolysis reaction and highly reduced selectivity for alpha-D-glucose 1-phosphate, versus alpha-D-xylose 1-phosphate, in the synthesis reaction with 10fold reduced binding of alpha-D-glucose 1-phosphate compared to the wild-type enzyme
L31A
mutation decreases the strong protective effect of phosphate at 10 or 100 mM against inactivation at 45°C and subunit dissociation enforced by imidazole. Loss of stability appears to be largely due to weakened affinity for orthophosphate binding
R141A
mutation disrupts the strong protective effect of phosphate at 10 or 100 mM against inactivation at 45°C and subunit dissociation enforced by imidazole. Loss of stability appears to be largely due to weakened affinity for orthophosphate binding
R226A
-
site-directed mutagenesis, mutant enzyme shows 4fold increased inactivation rate during subunit dissociation at 30°C in absence of an oxyanion, but similar stability in presence of 5 mM sulfate or phosphate compared to the wild-type enzyme
R234A
-
site-directed mutagenesis, mutant enzyme shows 4fold reduced inactivation rate during subunit dissociation at 30°C in absence of an oxyanion, but reduced stability in presence of 5 mM sulfate or phosphate compared to the wild-type enzyme, 8fold reduced affinity for phosphate
R242A
-
site-directed mutagenesis, mutant enzyme shows 4fold reduced inactivation rate during subunit dissociation at 30°C in absence of an oxyanion, but reduced stability in presence of 5 mM phosphate compared to the wild-type enzyme, 20fold reduced affinity for phosphate
S174A
mutation decreases the strong protective effect of phosphate at 10 or 100 mM against inactivation at 45°C and subunit dissociation enforced by imidazole. Loss of stability appears to be largely due to weakened affinity for orthophosphate binding
S224A
-
site-directed mutagenesis, mutant enzyme shows 4fold increased inactivation rate during subunit dissociation at 30°C in absence of an oxyanion, but similar stability in presence of 5 mM sulfate or phosphate compared to the wild-type enzyme
S238A
-
site-directed mutagenesis, mutant enzyme shows 4fold increased inactivation rate during subunit dissociation at 30°C in absence of an oxyanion, but similar stability in presence of 5 mM sulfate or phosphate compared to the wild-type enzyme
T28A
mutation disrupts the strong protective effect of phosphate at 10 or 100 mM against inactivation at 45°C and subunit dissociation enforced by imidazole. Loss of stability appears to be largely due to weakened affinity for orthophosphate binding
D339A
-
significantly reduced activity
E382A
-
significantly reduced activity
E88A
-
significantly reduced activity
H341A
-
significantly reduced activity
H571L
-
significantly reduced activity
T378G
-
significantly reduced activity
Y280A
-
significantly reduced activity
D238A
-
15fold decrease in Vmax, 10fold decrease in Km for glucose 1-phosphate, 10fold increase in Ka for AMP, 10-20fold increase in Ki for glucose
D238N
-
15fold decrease in Vmax, 10fold decrease in Km for glucose 1-phosphate, 10fold increase in Ka for AMP, 10-20fold increase in Ki for glucose
F285L
-
2fold decrease in Vmax, 10fold decrease in affinity for caffeine, 3fold increase in Ka for AMP
N284A
-
3fold decrease in Vmax, 2fold increase in Ki for glucose
N284D
-
10fold reduction of Vmax, 10fold increase in Ki for glucose
F39L
-
mutant with enhanced thermostability and resistance to proteolytic degradation
F39L/N135S
-
mutant with enhanced thermostability and resistance to proteolytic degradation
F39L/N135S/T706I
-
mutant with enhanced thermostability and resistance to proteolytic degradation
F39L/T706I
-
mutant with enhanced thermostability and resistance to proteolytic degradation
N135S
-
mutant with enhanced thermostability
N135S/T706I
-
mutant with enhanced thermostability and resistance to proteolytic degradation
T706I
-
mutant with enhanced thermostability and resistance to proteolytic degradation
H185A
-
kM-valaue for maltotriose is 2.2fold higher than wild-type value, kcat for maltotriose is 34fold lower than wild-type value
K308A
-
kM-valaue for maltotriose is nearly identical to wild-type value, kcat for maltotriose is 225fold lower than wild-type value
R303A
-
kM-valaue for maltotriose is 1.1fold higher than wild-type value, kcat for maltotriose is 155fold lower than wild-type value
additional information