Information on EC 4.2.2.21 - chondroitin-sulfate-ABC exolyase

Word Map on EC 4.2.2.21
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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
4.2.2.21
-
RECOMMENDED NAME
GeneOntology No.
chondroitin-sulfate-ABC exolyase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
Exolytic removal of Delta4-unsaturated disaccharide residues from the non-reducing ends of both polymeric chondroitin/dermatan sulfates and their oligosaccharide fragments.
show the reaction diagram
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
chondroitin sulfate degradation I (bacterial)
-
-
dermatan sulfate degradation I (bacterial)
-
-
SYSTEMATIC NAME
IUBMB Comments
chondroitin-sulfate-ABC exolyase
This enzyme degrades a variety of glycosaminoglycans of the chondroitin-sulfate- and dermatan-sulfate type. Chondroitin sulfate, chondroitin-sulfate proteoglycan and dermatan sulfate are the best substrates but the enzyme can also act on hyaluronan at a much lower rate. Keratan sulfate, heparan sulfate and heparin are not substrates. The related enzyme EC 4.2.2.20, chondroitin-sulfate-ABC endolyase, has the same substrate specificity but produces a mixture of oligosaccharides of different sizes that are ultimately degraded to tetra- and disaccharides [4]. Both enzymes act by the removal of a relatively acidic C-5 proton of the uronic acid followed by the elimination of a 4-linked hexosamine, resulting in the formation of an unsaturated C4---C5 bond on the hexuronic acid moiety of the products [4,6].
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
strain NCTC 4636, growth on medium containing chondroitin sulfate C
-
-
Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
bovine nasal cartilage proteoglycan
2-acetamido-2-deoxy-3-O-(3-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose + bovine nasal cartilage proteoglycan core
show the reaction diagram
chondroitin
?
show the reaction diagram
chondroitin 4-sulfate
4-O-sulfated chondroitin disaccharide
show the reaction diagram
-
-
the major product
-
?
chondroitin 4-sulfate
?
show the reaction diagram
chondroitin 4-sulfate
unsaturated disaccharide
show the reaction diagram
-
-
-
-
?
chondroitin 6-sulfate
?
show the reaction diagram
-
-
-
-
?
chondroitin 6-sulfate
unsaturated disaccharide
show the reaction diagram
chondroitin sulfate
unsaturated sulfated disaccharide
show the reaction diagram
-
-
-
-
?
chondroitin sulfate A
?
show the reaction diagram
chondroitin sulfate A
DELTA4,5-unsaturated disaccharide
show the reaction diagram
chondroitin sulfate A
unsaturated sulfated disaccharide
show the reaction diagram
-
-
-
-
?
chondroitin sulfate B
DELTA4,5-unsaturated disaccharide
show the reaction diagram
-
-
-
-
?
chondroitin sulfate B
unsaturated sulfated disaccharide
show the reaction diagram
-
-
contains 2-acetamido-2-deoxy-3-O-(P-n-gluco-4-enepyranosyluronic acid)-4-O-sulfo-n-galactose
-
?
chondroitin sulfate C
?
show the reaction diagram
chondroitin sulfate C
DELTA4,5-unsaturated disaccharide
show the reaction diagram
chondroitin sulfate C
unsaturated sulfated disaccharide
show the reaction diagram
-
-
-
-
?
chondroitin sulfate D
?
show the reaction diagram
chondroitin sulfate D
unsaturated sulfated disaccharide
show the reaction diagram
-
-
contains 2-acetamido-2-deoxy-3-O-(P-n-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose
-
?
chondroitin sulfate E
?
show the reaction diagram
chondroitin sulfate E
unsaturated sulfated disaccharide
show the reaction diagram
-
-
-
-
?
chondroitin sulfate proteoglycan
?
show the reaction diagram
chondroitin-4-sulfate
2-acetamido-2-deoxy-3-O-(3-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose
show the reaction diagram
chondroitin-6-sulfate
unsaturated sulfated disaccharides
show the reaction diagram
-
-
-
-
?
decorin
?
show the reaction diagram
-
-
-
-
?
dermatan sulfate
2-acetamido-2-deoxy-3-O-(3-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose + 2-acetamido-2-deoxy-3-O-(3-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose + 2-acetamido-2-deoxy-3-O-(3-D-gluco-4-enepyranosyluronic acid)-4,6-O-bis-sulfo-D-galactose
show the reaction diagram
-
-
-
-
?
dermatan sulfate
?
show the reaction diagram
dermatan sulfate
unsaturated disaccharide
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside + H2O
GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc + GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside + H2O
GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-2-pyridinaminoside + 2 H2O
GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc + GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside + 2 H2O
GlcA-beta-(1->3)-GalNAc + GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-2-pyridinaminoside + H2O
GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside + H2O
GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside + H2O
GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside + 2 H2O
GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc4S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside + 2 H2O
GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
GlcA-beta-(1->3)-GlcNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside + H2O
GlcA-beta-(1->3)-GlcNAc + DELTA4GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
high molecular weight hyaluronic acid D
?
show the reaction diagram
-
relative activity: 1.1%
-
-
?
hyaluronan
?
show the reaction diagram
hyaluronic acid
?
show the reaction diagram
IdoA-beta-(1->3)-GalNAc-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside + H2O
IdoA-beta-(1->3)-GalNAc + DELTA4GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-(1->4)-GlcA-beta-(1->3)-GalNAc6S-beta-2-pyridinaminoside
show the reaction diagram
-
-
-
-
?
low molecular weight hyaluronic acid D
?
show the reaction diagram
-
relative activity: 1.1%
-
-
?
additional information
?
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
for the monovalent ions tested, increasing the concentration of Na+, K+, or CS+ chloride from 0 to 0.1 M increases the activity against all substrates. Further increases in salt concentration reduces the activity dramatically, with 50% inhibition occurring at 0.15 M and a nearly complete inhibition at 0.4 M salt
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
Ca2+
-
10 mM, partial inhibition
Fe3+
-
10 mM, complete inhibition
heparin
heparitin sulfate
-
-
keratosulfate
-
-
Mn2+
-
10 mM, partial inhibition
N-desulfated heparin
-
50% inhibition at 0.150 mg/ml for enzyme I and 0.025 mg/ml for enzyme II
-
NaCl
-
optimal concentration 62.5 mM for substrate chondroitin 6-sulfate, 50% inhibition at 125 mM, optimal concentration 125 mM for substrate dermatan sulfate, 50% inhibition at 250 mM
phosphate
-
10 mM, 10% residual activity
additional information
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
NaCl
-
optimal concentration 62.5 mM for substrate chondroitin 6-sulfate, inhibitory above 125 mM, optimal concentration 125 mM for substrate dermatan sulfate, inhibitory above 250 mM
phosphate
-
activity in 20 mM phosphate buffer is less than half of the activity in 50 mM phosphate buffer, maximum activity for isoenzyme I in 50 mM, isoenzyme II in 50-100 mM phosphate
Sodium acetate
-
required
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0015 - 0.0161
chondroitin 4-sulfate
0.0012 - 0.036
chondroitin 6-sulfate
0.034 - 0.202
chondroitin sulfate A
0.012 - 0.195
chondroitin sulfate C
0.08
chondroitin-6-sulfate
-
pH 8.0, 37C
0.0025 - 0.09
dermatan sulfate
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
16.67 - 867
chondroitin 4-sulfate
0.17 - 652
chondroitin 6-sulfate
10.38 - 263.2
chondroitin sulfate A
4.41 - 173
chondroitin sulfate C
0.072 - 450
dermatan sulfate
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1000
chondroitin 4-sulfate
Proteus vulgaris
-
wild type enzyme, in 50mM Tris/HCl, pH 8.0, at 37C
2137
23.3 - 2200
chondroitin 6-sulfate
1675
8.3 - 1000
dermatan sulfate
907
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
1.45
-
30C, pH 7.5
14.8
-
substrate hyaluronan, pH 8.0
34
-
pH 8.0, 37C
34.8
-
substrate chondroitin sulfate E, pH 8.0
37.5
-
pH 8.0, 37C
43
-
pH 8.0, 37C
54.2
-
substrate chondroitin sulfate D, pH 8.0
69.8
-
substrate chondroitin, pH 8.0
122.3
-
substrate dermatan sulfate, pH 8.0
174.6
-
substrate chondroitin 6-sulfate, pH 8.0
290.6
-
substrate chondroitin 4-sulfate, pH 8.0
additional information
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5
-
substrate hyaluronic acid
6
-
substrate chondroitin
6.2
-
substrate chondroitin
6.6
-
substrate chondroitin sulfate A, or C
6.8
-
substrate hyaluronic acid
9
-
inactive
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
25 - 40
-
no significant reduction in activity at temperatures in the range of 25-40 C
37
-
15% residual activity
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.9
-
isoelectric focusing, isoenzyme I
8.25
-
and 8.0, isoelectric focusing
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
32000
-
1 * 86000 + 1 * 32000, SDS-PAGE
86000
-
1 * 86000 + 1 * 32000, SDS-PAGE
97000 - 116000
-
chABC alone migrates between 97 kDa and 116 kDa, SDS-PAGE
100000
-
SDS-PAGE
104000
-
x * 108000, isoenzyme I, x * 104000, isoenzyme II, SDS-PAGE
108000
-
x * 108000, isoenzyme I, x * 104000, isoenzyme II, SDS-PAGE
110000
-
x * 110000, SDS-PAGE, x * 112614, calculated
112614
-
x * 110000, SDS-PAGE, x * 112614, calculated
120000
-
gel filtration
150000
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
heterodimer
-
1 * 86000 + 1 * 32000, SDS-PAGE
monomer
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
crystal structure identifies additional structurally conserved residues potentially involved in catalysis. A conserved cluster located 12 A from the catalytic tetrad is shown. A His in this cluster is essential for catalysis of dermatane sulfate but not chondroitin sulfate. The enzyme utilizes a single substrate-binding site while having two partially overlapping active sites catalyzing the respective reactions. The spatial separation of the two sets of residues suggests a substrate-induced conformational change that brings all catalytically essential residues close together
-
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
25 - 40
-
above 40C the enzyme gets denaturated
37
-
chABC loses ist enzymatic activity rapidly at 37C, while thermostabilized chABC remains active at 37C in vitro for up to 4 weeks
40
-
30 min, 23% loss of activity
45
-
dramatic loss of activity
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
microtube-encapsulated chABC is biologically active for 2 weeks
-
sensitive to lyophilization and freezing and thawing, both isoenzyme I and II
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20C, 12 months, no loss of activity
-
4C, two weeks, 70-80% residual activity, both isoenzyme I and II
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Hi-Trap Ni-chelate column chromatography, gel filtration
-
isoform chondroitinase AC, cell disruption by ultrasound, under mild conditions, solubilization of most of enzyme activity
-
using a combination of DEAE-, Ni-NTA-, Mono-S HR 10/10, and HiLoad 16/60 Superdex 200-columns
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in Escherichia coli
-
expressed in Escherichia coli as a His-tagged fusion protein
-
expressed in Escherichia coli BL21(DE3) cells
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
E628D
-
mutant shows no activity
E628Q
-
Km (mM) (chondroitin sulfate A) 0.158, (chondroitin sulfate C) 0.035, kcat (1/sec) (chondroitin sulfate A) 10.38, (chondroitin sulfate B) 4.41, no activity toward dermatan sulfate
H344A
-
Km (mM) (chondroitin sulfate A) 0.202, (chondroitin sulfate C) 0.134, kcat (1/sec) (chondroitin sulfate A) 92.66, (chondroitin sulfate B) 35.71, no activity toward dermatan sulfate
H344D
-
mutant shows no activity
H344E
-
mutant shows no activity
H344N
-
Km (mM) (chondroitin sulfate A) 0.039, (chondroitin sulfate C) 0.084, (dermatan sulfate) 0.09, kcat (1/sec) (chondroitin sulfate A) 42.2, (chondroitin sulfate B) 18.7, (dermatan sulfate) 9.06
H344Q
-
Km (mM) (chondroitin sulfate A) 0.073, kcat (1/sec) (chondroitin sulfate A) 16.78, no activity toward dermatan sulfate or chondroitin sulfate C
H345A
-
Km (mM) (chondroitin sulfate A) 0.171, (chondroitin sulfate C) 0.195, kcat (1/sec) (chondroitin sulfate A) 63, (chondroitin sulfate B) 30.88, no activity toward dermatan sulfate
H345D/E
-
mutant shows no activity
H345N
-
Km (mM) (chondroitin sulfate A) 0.061, (chondroitin sulfate C) 0.026, kcat (1/sec) (chondroitin sulfate A) 21, (chondroitin sulfate B) 6.6, no activity toward dermatan sulfate
H345Q
-
Km (mM) (chondroitin sulfate A) 0.045, (chondroitin sulfate C) 0.102, kcat (1/sec) (chondroitin sulfate A) 23.46, (chondroitin sulfate B) 10.85, no activity toward dermatan sulfate
H453A
-
Km (mM) (chondroitin sulfate A) 0.038, (chondroitin sulfate C) 0.02, (dermatan sulfate) 0.044, kcat (1/sec) (chondroitin sulfate A) 17, (chondroitin sulfate B) 6.41, (dermatan sulfate) 5.8
H453N
-
Km (mM) (chondroitin sulfate A) 0.034, (chondroitin sulfate C) 0.012, kcat (1/sec) (chondroitin sulfate A) 13.15, (chondroitin sulfate B) 6.8, no activity toward dermatan sulfate
H454/D/N/Q
-
mutant shows no activity
H454A
-
mutant shows no activity
Q173A
-
Km (mM) (chondroitin sulfate A) 0.102, (chondroitin sulfate C) 0.050, (dermatan sulfate) 0.071, kcat (1/sec) (chondroitin sulfate A) 123, (chondroitin sulfate B) 33, (dermatan sulfate) 6.8
R172A
-
mutant shows no activity
R267A
-
Km (mM) (chondroitin sulfate A) 0.109, (chondroitin sulfate C) 0.098, (dermatan sulfate) 0.071, kcat (1/sec) (chondroitin sulfate A) 205, (chondroitin sulfate B) 61.7, (dermatan sulfate) 4.1
R514A
-
mutant shows no activity
Y461A
-
mutant shows no activity
Y461F
-
mutant shows no activity
E608A
-
the mutant does not show detectable activity on either chondroitin 6-sulfate or dermatan sulfate
E653A
-
no enzymic activity
E653D
-
no enzymic activity
E653Q
-
5fold increase in Km-value
H452A
-
the mutant shows similar Km values to the wild type enzyme but a 100fold reduced catalytic efficiency
H453A
-
the mutant does not show detectable activity on either chondroitin 6-sulfate or dermatan sulfate
H456A
-
the mutant shows about 3fold reduction in catalytic efficiency
H501A
-
no enzymic activity
H501K
-
no enzymic activity
H501R
-
no enzymic activity
H561A
-
increase in Km-values
H712A
-
increase in Km-values
R513A
-
the mutant does not show detectable activity on either chondroitin 6-sulfate or dermatan sulfate
R560A
-
no enzymic activity
Y460A
-
the mutant does not show detectable activity on either chondroitin 6-sulfate or dermatan sulfate
Y508A
-
no enzymic activity
Y508F
-
30fold increase in Km-value
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
analysis
biotechnology
-
preservation of ChABC activity during release by immobilizing ChABC in chitosan nerve conduits and encapsulating ChABC in poly(DL-lactic acid) microspheres using an appropriate stabilizer. Immobilizing ChABC in nerve conduitss markedly improves its stability. The activity of ChABC that is immobilized in chitosan nerve conduits by ionic bonding is 0.07 U/mg. 48% of this activity is retained at 48 h after immobilization. Poly(DL-lactic acid) microspheres, fabricated by the double emulsion method, are applied as carriers in the controlled release of ChABC. Stabilizers, including nanogold of 10 nm, polylysine of Mw 500-2000 and polylysine of Mw 20000-30000, are added to microspheres to maintain the activity of ChABC. Polylysine stabilizes ChABC most effectively. The ChABC activity is 0.0162 U/ml after seven days of release
medicine
synthesis
-
Production of enzyme for industrial use. Induction of enzyme by addition of chondroitin sulfate C to growth medium. Optimal conditions are pH 8.0, 25C, plus the addition of yeast extract, peptone and casamino acid. Induction is inhibited by chloramphenicol and actinomycin D