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3.2.1.23: beta-galactosidase

This is an abbreviated version!
For detailed information about beta-galactosidase, go to the full flat file.

Word Map on EC 3.2.1.23

Reaction

beta-D-galactopyranosyl-(1-4)-beta-D-galactopyranosyl-(1-6)-beta-D-galactopyranosyl-(1-3)-beta-D-galactopyranose
+ 3 H2O = 4 beta-D-galactopyranose

Synonyms

Aabeta-gal, Acid beta-galactosidase, B-GAL, BbgI, BbgII, BbgIII, BbgIV, beta galactosidase, beta-D-galactohydrolase, beta-D-galactosidase, beta-D-galactoside galactohydrolase, beta-D-glactanase, beta-D-lactosidase, beta-gal, beta-Gal 1, beta-Gal 2, beta-Gal II, beta-galactosidase, beta-galactosidase I, beta-galactosidase II, beta-galactosidase III, beta-galactosidase IV, beta-galase, beta-lactosidase, betagal, betaGly4, betaGS, BGA, BgaB, BgaBM, bgaD, BgaH, BGAL, BGAL1, BGAL10, BGAL11, BGAL12, BGAL13, BGAL14, BGAL15, BGAL16, BGAL17, BGAL2, BGAL3, BGAL4, BGAL5, BGAL6, BGAL7, BGAL8, BGAL9, BgalA, BgAP, BgaS, BgaX, BGL1, BglAp, BGT I, BGT II, cold-active beta-galactosidase, CTP-beta-gal, driselase, EABase, endo-beta-galactosidase, Exo-(1-->4)-beta-D-galactanase, exo-beta-(1->3)-D-galactanase, Gal-2, Gal-5, GAL1, Gal2, Gal3, Gal4, GALA, galactanase, galactosidase, galactosidase, beta, GALB, gherkin lactase, H-BgaS, hcbetagal, Hlac_2868, Hydrolact, LacA, LACS, lactase, lactase phlorizin hydrolase, lactosylceramidase II, Lactozym, Lactozym 3000L, LPH, Maxilact, Maxilact-L/2000, MeBglD2, More, ONPGase, Oryzatym, p-nitrophenyl beta-galactosidase, PF1208, PRGH1, S 2107, SA-beta-GAL, SA-betagal, senescence-associated beta-galactosidase, SPD_0065 protein, SR12 protein, Ss beta-gal, SSO3019, SSU0587, Sumiklat, Trilactase, XC1214, XG-specific beta-galactosidase, YesZ, YH4502, ZD410

ECTree

     3 Hydrolases
         3.2 Glycosylases
             3.2.1 Glycosidases, i.e. enzymes that hydrolyse O- and S-glycosyl compounds
                3.2.1.23 beta-galactosidase

Engineering

Engineering on EC 3.2.1.23 - beta-galactosidase

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PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
E157G
site-directed mutagenesis, altered kinetics compared to the wild-type enzyme
E313G
site-directed mutagenesis, altered kinetics compared to the wild-type enzyme
E229D
-
site-directed mutagenesis, enzyme BgaS7a, the mutant shows slightly increased activity compared to the wild-type enzyme
E229D/G803D
-
site-directed mutagenesis, inactive mutant
E229D/V405A
-
site-directed mutagenesis, enzyme BgaS7, the mutant shows similar thermal optima and thermostabilities as BgaS, but shows a 2.5fold increase in catalytic activity at 15°C and hydrolyzes 80% of lactose in skim milk in less than half the time of BgaS at 2.5°C
E229D/V405A/G803D
-
site-directed mutagenesis, enzyme BgaS6, the mutant shows similar thermal optima and thermostabilities as BgaS, the mutant shows slightly increased activity compared to the wild-type enzyme
G803D
-
site-directed mutagenesis, inactive mutant
V405A
-
site-directed mutagenesis, enzyme BgaS7b, the mutant shows slightly increased activity compared to the wild-type enzyme
V405A/G803D
-
site-directed mutagenesis, inactive mutant
E229D
-
site-directed mutagenesis, enzyme BgaS7a, the mutant shows slightly increased activity compared to the wild-type enzyme
-
E229D/G803D
-
site-directed mutagenesis, inactive mutant
-
G803D
-
site-directed mutagenesis, inactive mutant
-
V405A/G803D
-
site-directed mutagenesis, inactive mutant
-
S259F/P261T/L262S/G263S
mutant shows slightly reduced affinity for substrate (Km: 3.76 mM), 8.5fold reduction in inhibition by galactose, maximal activity lower than wild-type, pH stability lower than wild-type
N140C
the mutant shows improved activity compared to the wild type enzyme
N140C/W806F
the mutant shows improved activity compared to the wild type enzyme
W806F
the mutant shows improved activity compared to the wild type enzyme
N140C
-
the mutant shows improved activity compared to the wild type enzyme
-
N140C/W806F
-
the mutant shows improved activity compared to the wild type enzyme
-
W806F
-
the mutant shows improved activity compared to the wild type enzyme
-
E359A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The E359A mutant exhibits no activity
F349A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The F349A, R111A, and W187A mutant enzyme in the presence of galactose shows remaining activity of 65%
F349S
mutant exhibits the highest activity in the presence of galactose relative to the activity measured in the absence of galactose among the tested mutant enzymes at position 349. The Ki-value for galactose of the F349S mutant (160 mM), which is 13fold that of the wild-type enzyme, is the highest among the reported values of beta-galactosidase. The wild-type enzyme hydrolyzes 62% of 100 g lactose/l with the addition of 30 g galactose/l, whereas the F349S mutant hydrolyzes more than 99%
H362A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The H362A mutant in the presence of galactose exhibits remaining activity below 30%
I44A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The I44A mutant in the presence of galactose exhibits remaining activity below 30%
N149A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The N149A mutant in the presence of galactose exhibits remaining activity below 30%
R111A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The F349A, R111A, and W187A mutant enzyme in the presence of galactose shows remaining activity of 46%
S41A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The S41A mutant in the presence of galactose exhibits remaining activity below 30%
W187A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The F349A, R111A, and W187A mutant enzyme in the presence of galactose shows remaining activity of 44%
W319A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The W319A mutant in the presence of galactose exhibits remaining activity below 30%
Y281A
30 g galactose/l. The wild-type enzyme exhibits 13% remaining activity relative to the activity observed in the absence of galactose. The Y281A mutant exhibits no activity
D429A
-
the mutant has wild type activity
D453A
-
inactive
E354A
-
the activity of the E354A mutant with nonactivated natural substrates is 1100fold lower than that of the wild type enzyme, while its activity is only 10fold lower when assayed with 2,4-dinitrophenyl 2-acetamido-2-deoxy-alpha-D-galactopyranosyl-(1-3)-[alpha-L-fucopyranosyl-(1-2)]-beta-D-galactopyranoside
E467A
-
the mutant has wild type activity
E506A
-
inactive
E416Q
the mutant enzyme does not have a Mg2+ bound at the active site even at high Mg2+ concentrations (200 mM), low catalytic activity and the pH profile is very different from that of the native enzyme
E416V
the mutant enzyme does not have a Mg2+ bound at the active site even at high Mg2+ concentrations (200 mM), low catalytic activity and the pH profile is very different from that of the native enzyme
H418E
the mutant shows low catalytic activity
H418F
the mutant shows low catalytic activity, the variant has reduced stability, binds Mg2+ weakly and cannot be crystallized
H418N
the mutant shows low catalytic activity
N460T
analysis of rate constants and activation thermodynamics to demonstrate the valuable mechanistic details of enzymes that can be obtained from studies of this type
E416Q
-
the mutant enzyme does not have a Mg2+ bound at the active site even at high Mg2+ concentrations (200 mM), low catalytic activity and the pH profile is very different from that of the native enzyme
-
E416V
-
the mutant enzyme does not have a Mg2+ bound at the active site even at high Mg2+ concentrations (200 mM), low catalytic activity and the pH profile is very different from that of the native enzyme
-
R109K
-
the mutant shows decreased specific activity towards 4-nitrophenyl-beta-D-galactopyranoside compared to the wild type enzyme, the apparent Km values toward the natural substrates lactose and lactosucrose are strongly increased
R109V
-
the mutant shows increased specific activity towards 4-nitrophenyl-beta-D-galactopyranoside compared to the wild type enzyme, the apparent Km values toward the natural substrates lactose and lactosucrose are strongly increased
R109W
-
the mutant shows increased specific activity towards 4-nitrophenyl-beta-D-galactopyranoside compared to the wild type enzyme, the apparent Km values toward the natural substrates lactose and lactosucrose are strongly increased
R109K
-
the mutant shows decreased specific activity towards 4-nitrophenyl-beta-D-galactopyranoside compared to the wild type enzyme, the apparent Km values toward the natural substrates lactose and lactosucrose are strongly increased
-
R109V
-
the mutant shows increased specific activity towards 4-nitrophenyl-beta-D-galactopyranoside compared to the wild type enzyme, the apparent Km values toward the natural substrates lactose and lactosucrose are strongly increased
-
R109W
-
the mutant shows increased specific activity towards 4-nitrophenyl-beta-D-galactopyranoside compared to the wild type enzyme, the apparent Km values toward the natural substrates lactose and lactosucrose are strongly increased
-
D332N
-
mutation seriously reduces catalytic activity
R148S
-
mutation has no effect on catalytic activity
E491A
the mutant shows wild type optimal temperature, but displays an optimal pH at 6.5-7.0
L317F
-
maximal velocity deviates from that of wild-type enzyme only at lower temperatures, in 2 mM Mg2+. This temperature-dependent effect can be suppressed by increasing the Mg2+ concentration
E173N
mutant enzyme shows no activity
E389N
mutant enzyme shows no activity
E446N
beta-fucosidase activity is 26.49% compared to wild-type activity, beta-glucosidase activity is 21.37% compared to wild-type activity, beta-galactosidase activity is 15.7% compared to wild-type activity
N172A
beta-fucosidase activity is 18.38% compared to wild-type activity, beta-glucosidase activity is 17.65% compared to wild-type activity, beta-galactosidase activity is 13.4% compared to wild-type activity
T29A/V213I/L217M/N277H/I387V/R491C/N496D
large range mutant screening after direct chemical evolution, the mutant variant YG6762 has nucleotide changes in 13 sites: T30C, A85G, C621A, G637A, T649A, A829V, T912G, C924T, A1159G, G1242C, C1471T, A1486G, and C1497A, the mutant YG6762 shows 4.9-7.5fold increased activity, dependent on the reaction temperature, but decreased thermostability, compared to the wild-type enzyme, overview, revertion of the mutation at each single of the 8 mutation sites results in decreased activity of the altered mutant, especially when reverting residue 277 to Asn, overview
F359Q
compared to wild-type enzyme the mutant enzyme is less stable at 75°C, the optimum is similar to that of wild-type enzyme. Km of the mutant enzyme is increased about 2fold and the kcat is increased by 32.3%
F441Y
F359Q
-
compared to wild-type enzyme the mutant enzyme is less stable at 75°C, the optimum is similar to that of wild-type enzyme. Km of the mutant enzyme is increased about 2fold and the kcat is increased by 32.3%
-
F441Y
E184A
-
site-directed mutagenesis, the mutant functions as an efficient thioglycoligase, which synthesises thiogalactosides with linkages to the 3 and 4 positions of glucosides and galactosides in high yields, the mutant shows reduced galactohydrolase activity compared to the wild-type enzyme
E184Q
-
site-directed mutagenesis, the mutant does not function as a thioglycoligase, the mutant shows reduced galactohydrolase activity compared to the wild-type enzyme
additional information