Information on EC 3.2.1.108 - lactase

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The expected taxonomic range for this enzyme is: Eukaryota, Bacteria

EC NUMBER
COMMENTARY hide
3.2.1.108
-
RECOMMENDED NAME
GeneOntology No.
lactase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
lactose + H2O = D-galactose + D-glucose
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hydrolysis
hydrolysis of O-glycosyl bond
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Galactose metabolism
-
-
lactose degradation III
-
-
Metabolic pathways
-
-
SYSTEMATIC NAME
IUBMB Comments
lactose galactohydrolase
The enzyme from intestinal mucosa is isolated as a complex that also catalyses the reaction of EC 3.2.1.62 glycosylceramidase. cf. EC 3.2.1.33 amylo-alpha-1,6-glucosidase.
CAS REGISTRY NUMBER
COMMENTARY hide
9031-11-2
-
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
BALB/c mouse
-
-
Manually annotated by BRENDA team
Mus musculus BALB/c
BALB/c mouse
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
lactase-phlorizin hydrolase complex
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
metabolism
-
metabolism of ginsenosides in the intestinal flora of rats, mass spectrometric product analysis, detailed overview; the enzyme is responsible for the hydrolysis of prenylated flavonoids (icariin, epimedin A, epimdin B, epimedin C, and baohuoside I) of Yinyanghuo (Herba epimdii)
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
2-O-beta-D-galactopyranosyl-D-xylose + H2O
D-galactose + D-xylose
show the reaction diagram
-
-
-
-
?
3-O-beta-D-galactopyranosyl-D-xylose + H2O
D-galactose + D-xylose
show the reaction diagram
-
-
-
-
?
4-O-beta-D-galactopyranosyl-D-xylose + H2O
D-galactose + D-xylose
show the reaction diagram
-
-
-
-
?
5-bromo-4-chloro-3-indolyl-beta-D-fucopyranoside + H2O
?
show the reaction diagram
-
37C, 1 hour, full-length lactase, mature lactase, cytosolic form of mature lactase
-
-
?
5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside + H2O
?
show the reaction diagram
baohuoside I + H2O
? + D-glucose
show the reaction diagram
cellobiose + H2O
2 beta-D-glucose
show the reaction diagram
cellotetraose + 3 H2O
4 beta-D-glucose
show the reaction diagram
cellotriose + H2O
beta-D-glucose
show the reaction diagram
cellulose + H2O
beta-D-glucose
show the reaction diagram
daidzein 7-glucoside + H2O
quercetin + D-glucose
show the reaction diagram
-
-
-
-
?
daidzein-7-glucoside + H2O
quercetin + D-glucose
show the reaction diagram
-
-
-
-
?
epimedin A + H2O
? + D-glucose
show the reaction diagram
epimedin B + H2O
? + D-glucose
show the reaction diagram
epimedin C + H2O
? + D-glucose
show the reaction diagram
fluorescein-di-beta-D-galactopyranoside + H2O
?
show the reaction diagram
-
only cytosolic form of mature lactase
-
-
?
genistein-7-glucoside + H2O
genistein + D-glucose
show the reaction diagram
-
-
-
-
?
gentiobiose + H2O
2 beta-D-glucose
show the reaction diagram
-
0.7% of the activity with lactose
-
-
?
icariin + H2O
? + D-glucose
show the reaction diagram
lactose + H2O
D-galactose + D-glucose
show the reaction diagram
lactose + H2O
D-glucose + D-galactose
show the reaction diagram
lactose + H2O
galactose + D-glucose
show the reaction diagram
-
reaction is not inhibited by 2-fluoro-dinotrophenylglucoside
-
-
?
methyl-beta-D-glucoside + H2O
methanol + beta-D-glucose
show the reaction diagram
-
7.3% of the activity with lactose
-
-
?
o-nitrophenyl-beta-galactoside + H2O
o-nitrophenol + beta-D-galactose
show the reaction diagram
o-nitrophenyl-beta-glucoside + H2O
o-nitrophenol + beta-D-glucose
show the reaction diagram
-
13% of the activity with lactose
-
-
?
p-nitrophenyl-beta-galactoside + H2O
p-nitrophenol + beta-D-galactose
show the reaction diagram
p-nitrophenyl-beta-glucoside + H2O
p-nitrophenol + beta-D-glucose
show the reaction diagram
phenyl-beta-galactoside + H2O
phenol + beta-D-galactose
show the reaction diagram
-
0.1% of the activity with lactose
-
-
?
phlorizin
phloretin + D-glucose
show the reaction diagram
-
37C, 2h
-
-
?
phlorizin + H2O
?
show the reaction diagram
-
reaction is inhibited by 2-fluoro-dinotrophenylglucoside
-
-
?
phlorizin + H2O
phloretin + D-glucose
show the reaction diagram
quercetin-3-glucoside + H2O
quercetin + D-glucose
show the reaction diagram
-
reaction is marginally inhibited by 2-fluoro-dinotrophenylglucoside
-
-
?
quercetin-4'-glucoside + H2O
quercetin + D-glucose
show the reaction diagram
-
reaction is marginally inhibited by 2-fluoro-dinotrophenylglucoside
-
-
?
salicin + H2O
?
show the reaction diagram
-
1.6% of the activity with lactose
-
-
?
additional information
?
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
baohuoside I + H2O
? + D-glucose
show the reaction diagram
-
from Yinyanghuo (Herba Epimdii, YYH) is a popular Traditional Chinese Medicine tonic for kidney-reinforcing from Epimedium koreanum Nakai herb extract
-
-
?
epimedin A + H2O
? + D-glucose
show the reaction diagram
-
from Yinyanghuo (Herba Epimdii, YYH) is a popular Traditional Chinese Medicine tonic for kidney-reinforcing from Epimedium koreanum Nakai herb extract
-
-
?
epimedin B + H2O
? + D-glucose
show the reaction diagram
-
from Yinyanghuo (Herba Epimdii, YYH) is a popular Traditional Chinese Medicine tonic for kidney-reinforcing from Epimedium koreanum Nakai herb extract
-
-
?
epimedin C + H2O
? + D-glucose
show the reaction diagram
-
from Yinyanghuo (Herba Epimdii, YYH) is a popular Traditional Chinese Medicine tonic for kidney-reinforcing from Epimedium koreanum Nakai herb extract
-
-
?
icariin + H2O
? + D-glucose
show the reaction diagram
-
from Yinyanghuo (Herba Epimdii, YYH) is a popular Traditional Chinese Medicine tonic for kidney-reinforcing from Epimedium koreanum Nakai herb extract
-
-
?
lactose + H2O
D-galactose + D-glucose
show the reaction diagram
lactose + H2O
D-glucose + D-galactose
show the reaction diagram
additional information
?
-
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2-fluoro-dinitrophenylglucoside
-
specifically inhibits phlorizin hydrolase, lactase activity is inhibited slowly
cerebroside
-
bovine brain cerebroside
D-glucal
-
40% inhibition for 4-O-beta-D-galactopyranosyl-D-xylose and 75% inhibition for 3-O-beta-D-galactopyranosyl-D-xylose at 100 mM D-glucal, no increase of inhibition above 100 mM D-glucal
epigallocatechin-3-gallate
-
inhibition by epigallocatechin-3-gallate of lactase is alleviated about 1.7fold by proline-rich proteins
gluconolactone
-
-
N-(n-butyl)-deoxygalactojirimycin
-
-
NSP4
-
impairment of lactase activity observed during rotavirus infection results from an inhibitory action of the secreted non-structural rotavirus protein NSP4
-
phlorizin
thyroxine
-
administration of thyroxine to 8-day-old pups shows a decline in lactase activity
additional information
-
rotavirus impairs lactase enzymatic activity by an NSP4-dependant mechanism in brush border of human enterocyte-like Caco-2 cells, the infected brush border membranes show an enzyme with altered kinetics, overview
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
cortisone
-
administration of cortisone to 8-day-old pups augments lactase activity
additional information
-
determination of disaccharidase activities in intestinal biopsy samples show a highly significant correlation between lactase activity and the T/G-13915 genotype
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
22.2
2-O-beta-D-galactopyranosyl-D-xylose
-
100 mM sodium maleate buffer, pH 6.0, 25C
8.5
3-O-beta-D-galactopyranosyl-D-xylose
-
100 mM sodium maleate buffer, pH 6.0, 25C
58.8
4-O-beta-D-galactopyranosyl-D-xylose
-
100 mM sodium maleate buffer, pH 6.0, 25C
2.78 - 4.4
cellobiose
0.149
daidzein-7-glucoside
-
pH 6, 37C
0.085
genistein-7-glucoside
-
pH 6, 37C
5.1 - 30
lactose
0.002 - 0.44
phlorizin
0.046
quercetin-3-glucoside
-
pH 6, 37C
0.044
quercetin-4'-glucoside
-
pH 6, 37C
additional information
additional information
-
rotavirus infection decreases Vmax of LPH, overview
-
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2.1
daidzein-7-glucoside
Ovis aries
-
pH 6, 37C
6.5
genistein-7-glucoside
Ovis aries
-
pH 6, 37C
33.8
lactose
Ovis aries
-
pH 6, 37C
0.5
phlorizin
Ovis aries
-
pH 6, 37C
6.3
quercetin-3-glucoside
Ovis aries
-
pH 6, 37C
7.5
quercetin-4'-glucoside
Ovis aries
-
pH 6, 37C
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.074 - 0.126
epigallocatechin-3-gallate
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.00164
-
non-infected cells, lactase enzyme activity in cell homogenates
0.00167
-
rhesus monkey rotavirus-, RRV, infected cells, lactase enzyme activity in cell homogenates
0.002
-
mutant S218fsX224, mean lactase activity
0.0021
-
mutant Y1390X, mean lactase activity
0.00219
-
rhesus monkey rotavirus-, RRV, infected cells, lactase enzyme activity in brush border-enriched fraction
0.003
-
mutant G1363S, mean lactase activity
0.0033
-
rats are force-fed a low-strach diet, with thyroid hormone treatment
0.00344
-
non-infected cells, lactase enzyme activity in brush border-enriched fraction
0.00359
-
UV, psoralen-inactivated RRV infected cells, lactase enzyme activity in brush border-enriched fraction
0.0042
-
rats are fed a low-starch diet for 7 days
0.005
-
mutant Q268H, mean lactase activity; mutant S1666fsX1722, mean lactase activity
0.0058
-
rats are force-fed a sucrose diet, with thyroid hormone treatment
0.0067
-
rats are fed a low-starch diet, starved for 3 days, and thyroid hormones are injected daily after the diet
0.0083
-
rats are force-fed a low-strach diet, without thyroid hormone treatment; rats are force-fed a sucrose diet, without thyroid hormone treatment
0.01
-
rats are fed a high-starch diet for 7 days
0.012
-
rats are fed a low-starch diet, starved for 3 days
0.015
-
30 days old rat
0.07
-
18 days old rat
0.17
-
administration of thyroxine to 8-day-old pups, activity in suckling rat intestine
0.172
-
15 days old rat
0.27
-
control
0.29
-
administration of insuline to 8-day-old pups, activity in suckling rat intestine
0.36
-
administration of cortisone to 8-day-old pups, activity in suckling rat intestine
16.1
-
lactase
450
-
phlorizin hydrolase
additional information
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.6 - 6.2
-
-
5.8 - 6
-
hydrolysis of lactose
6
-
activity assay
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4 - 10
-
pH 4.0: about 60% of maximal activity, pH 10.0: about 50% of maximal activity
5 - 7
-
pH 5.0: about 70% of maximal activity, pH 7.0: about 65% of maximal activity
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
20
-
restoring of enzymatic activity of misfolded mutation G1363S by expression at 20C
25
-
activity assay
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
-
; fully differentiated, intestinal enterocyte-like cells
Manually annotated by BRENDA team
-
-
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
-
misfolded mutation G1363S
Manually annotated by BRENDA team
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
130000
-
molecular mass after N-glycosidase F treatment of LPH; N-glycosylated LPH, gel filtration
160000
-
cleaved intestinal mature form of LPH, determinated by pulse-chase experiments; N- and O-glycosylated LPH, gel filtration
220000
280000
-
hydrophilic enzyme form, gel filtration
320000
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
-
x * 140000, SDS-PAGE
homodimer
additional information
-
region LAC236 between R1647 and T1882 is implicated in the dimerization process of pro-enzyme
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
proteolytic modification
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.5
-
30% loss of activity after 0.5 min, 55% loss of activity after 120 min
288794
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
37
-
about 30% loss of lactase activity after 30 min
46
-
35 min, about 50% loss of phlorizin hydrolase activity. About 70% loss of lactase activity after 25 min
55
-
lactase and phlorizin hydrolase activity are identically heat inactivated
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
repeated freezing and thawing, activity declines fast
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20C, stable for several months
4C, stable for several weeks
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in Pichia pastoris
-
expression in Cos-1 cells
-
expression in HuH-7 cells
higher lactase activity and expression of LPH gene in jejunum of rat fed the high-carbohydrate/low-fat (HCT) diet compared with those fed a lowcarbohydrate/high-fat (LCT) diet is regulated at the transcription levels (nuclear run-on assay). In vitro binding of Cdx-2 to CE-LPH1 gene sequence as well as to SIF1 gene sequence is greater in rats fed a HCT diet than those fed a LCT diet
-
into the pNEB-193 vector
-
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D1711N
-
introduction of potential N-glycosilation site, no enzymic activity, probably due to altered protein folding pattern and reduced dimerization efficiency
E1612X
results in congenital lactase deficiency
G1363S
I1697N
-
introduction of potential N-glycosilation site, no enzymic activity, probably due to altered protein folding pattern and reduced dimerization efficiency
more |
-
CC13910, lactose intolerance, low lactase genotype, no predispose for cataracts with mutation of galactose-1-phosphate uridyl transferase
P1743S
-
introduction of potential N-glycosilation site, no enzymic activity, probably due to altered protein folding pattern and reduced dimerization efficiency
Q268H
-
congential lactase deficiency, CLD, mutation, DNA mutation c.804G->C, genotype compound heterozygote for Y1390X
R1587H
results in congenital lactase deficiency
S1666fsX1722
-
congential lactase deficiency, CLD, mutation, DNA mutation c.4998_5001delTGAG, genotype compound heterozygote for Y1390X
S218fsX224
-
congential lactase deficiency, CLD, mutation, DNA mutation c.653_654delCT, genotype compound heterozygote for Y1390X
S688P
results in congenital lactase deficiency
Y1390X
additional information
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
food industry
-
the enzyme is used for the production of dairy products
medicine
pharmacology