Information on EC 3.4.23.2 - pepsin B

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The expected taxonomic range for this enzyme is: Euteleostomi

EC NUMBER
COMMENTARY
3.4.23.2
-
RECOMMENDED NAME
GeneOntology No.
pepsin B
-
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
degradation of gelatin; little activity on hemoglobin. Specificity on B chain of insulin more restricted than that of pepsin A; does not cleave at Phe1-Val, Gln4-His or Gly23-Phe
show the reaction diagram
mechanism, concerted action of different pepsins
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
hydrolysis of peptide bond
-
-
endopeptidase
-
SYNONYMS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
EC 3.4.4.2
-
-
formerly
-
parapepsin I
-
-
-
-
gelatinase
-
-
-
-
additional information
-
the enzyme belongs to the A1 peptidase family
CAS REGISTRY NUMBER
COMMENTARY
9025-48-3
-
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
fragment
SwissProt
Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
Ac-Phe-Tyr
Ac-Phe + Tyr
show the reaction diagram
-
radio-labeled substrate
-
-
-
acetyl-Phe-L-diiodotyrosine + H2O
acetyl-L-phenylalanine + L-diiodotyrosine
show the reaction diagram
-
-
-
ir
FVNQHLCGSHLVEALYLVCGERGFFYTPKA + H2O
FVNQHLCGSHL + VEA + Leu + Tyr + LVCGERGF + Phe + YTPKA
show the reaction diagram
-
oxidized insulin B chain, cleavage site specificity determination
-
-
?
Gelatin + H2O
?
show the reaction diagram
Q2AB25
-
-
-
?
Gelatin + H2O
?
show the reaction diagram
-
liquefication
-
-
?
gelatin + H2O
? + ?
show the reaction diagram
-
-
-
ir
Hemoglobin + H2O
?
show the reaction diagram
-
-
-
-
?
Hemoglobin + H2O
?
show the reaction diagram
Q2AB25
-
-
-
?
Hemoglobin + H2O
?
show the reaction diagram
-
acid-denatured protein substrate
-
-
?
human serum albumin + H2O
? + ?
show the reaction diagram
-
-
-
ir
KPAEFLRL + H2O
KPAEF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
KPAEFVARL + H2O
KPAEF + ARL
show the reaction diagram
Q2AB25
-
-
-
?
KPAGFARL + H2O
KPAGF + ARL
show the reaction diagram
Q2AB25
-
-
-
?
KPAGFFRL + H2O
KPAGF + FRL
show the reaction diagram
Q2AB25
-
-
-
?
KPAGFGRL + H2O
KPAGF + GRL
show the reaction diagram
Q2AB25
-
-
-
?
KPAGFLRL + H2O
KPAGF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
KPAGFVRL + H2O
KPAGF + VRL
show the reaction diagram
Q2AB25
-
-
-
?
KPAKFLRL + H2O
KPAKF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
KPEEFFRL + H2O
KPEEF + FRL
show the reaction diagram
Q2AB25
-
-
-
?
KPEGFLRL + H2O
KPEGF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
KPGEFARL + H2O
KPGEF + ARL
show the reaction diagram
Q2AB25
-
-
-
?
KPGGF + LRL
KPGGF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
KPGGFARL + H2O
KPGGF + ARL
show the reaction diagram
Q2AB25
-
-
-
?
KPIGFLRL + H2O
KPIGF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
KPKEFFRL + H2O
KPKEF + FRL
show the reaction diagram
Q2AB25
-
-
-
?
KPKGFLRL + H2O
KPKGF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
proteins + H2O
acetyl-L-phenylalanyl-L-diiodotyrosine + H2O
show the reaction diagram
-
gelatin
-
ir
proteins + H2O
acetyl-L-phenylalanyl-L-diiodotyrosine + H2O
show the reaction diagram
-
more restricted specificity than pepsin A
-
ir
proteins + H2O
acetyl-L-phenylalanyl-L-diiodotyrosine + H2O
show the reaction diagram
-
more restricted specificity than pepsin A, little activity with hemoglobin
-
ir
Proteins + H2O
?
show the reaction diagram
-
enzyme formed from pepsinogen B, more restricted specificity than pepsin A
-
-
-
Proteins + H2O
?
show the reaction diagram
-
enzyme formed from pepsinogen B, more restricted specificity than pepsin A
-
-
-
Proteins + H2O
?
show the reaction diagram
-
enzyme formed from pepsinogen B, more restricted specificity than pepsin A
-
-
-
KPTGFLRL + H2O
KPTGF + LRL
show the reaction diagram
Q2AB25
-
-
-
?
additional information
?
-
-
milk clotting activity examined
-
-
-
additional information
?
-
-
little if any activity with hemoglobin
-
-
-
additional information
?
-
-
the enzyme shows milk clotting activity, the enzyme shows generally low proteolytic activity
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
Proteins + H2O
?
show the reaction diagram
-
enzyme formed from pepsinogen B, more restricted specificity than pepsin A
-
-
-
Proteins + H2O
?
show the reaction diagram
-
enzyme formed from pepsinogen B, more restricted specificity than pepsin A
-
-
-
Proteins + H2O
?
show the reaction diagram
-
enzyme formed from pepsinogen B, more restricted specificity than pepsin A
-
-
-
Gelatin + H2O
?
show the reaction diagram
-
liquefication
-
-
?
additional information
?
-
-
the enzyme shows milk clotting activity
-
-
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
CaCl2
-
5 mM, 1.13fold activation
CoCl2
-
5 mM, 1.17fold activation
MgCl2
-
5 mM, 1.13fold activation
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
EDTA
-
2 mM, 12.31% inhibition
NaCl
-
30%, activity of pepsin B decreases by 60-65%
pepstatin A
-
0.01 mM, 96.7% inhibition
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
additional information
-
activation of pepsinogen B to pepsin B rapidly at pH 2, more slowly at pH 4, pepsinogen B contains 1 mol phosphate per mol enzyme, function unclear
-
additional information
-
colchicin stimulates secretion
-
additional information
-
mechanism of activation
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
1.33
haemoglobin
-
-
-
152
Hemoglobin
-
pH 3.0, 37C
-
0.5
KPAAFFRL
Q2AB25
mutant enzyme F2119S
0.67
KPAAFFRL
Q2AB25
mutant enzyme Y13A/F219S
0.95
KPAEFARL
Q2AB25
wild-type enzyme
1.3
KPAEFARL
Q2AB25
mutant enzyme Y13A/F219S
0.35
KPAEFFRL
Q2AB25
mutant enzyme Y13A
0.42
KPAEFFRL
Q2AB25
mutant enzyme F2119S
0.71
KPAEFFRL
Q2AB25
mutant enzyme Y13A/F219S
4
KPAEFLRL
Q2AB25
mutant enzyme Y13A/F219S
2.5
KPAGFARL
Q2AB25
mutant enzyme F2119S
4
KPAGFARL
Q2AB25
wild-type enzyme
2.2
KPGGFARL
Q2AB25
mutant enzyme F2119S; wild-type enzyme
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
9.27
haemoglobin
-
-
-
32
Hemoglobin
-
pH 3.0, 37C
-
1.2
KPAAFFRL
Q2AB25
mutant enzyme F2119S
11
KPAAFFRL
Q2AB25
mutant enzyme Y13A/F219S
3.4
KPAEFARL
Q2AB25
wild-type enzyme
91
KPAEFARL
Q2AB25
mutant enzyme Y13A/F219S
1.2
KPAEFFRL
Q2AB25
mutant enzyme F2119S
2.5
KPAEFFRL
Q2AB25
mutant enzyme Y13A
18
KPAEFFRL
Q2AB25
mutant enzyme Y13A/F219S
113
KPAEFLRL
Q2AB25
mutant enzyme Y13A/F219S
130
KPAGFARL
Q2AB25
mutant enzyme F2119S
169
KPAGFARL
Q2AB25
wild-type enzyme
116
KPGGFARL
Q2AB25
mutant enzyme F2119S
134
KPGGFARL
Q2AB25
wild-type enzyme
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
-
56.14 U/mg protein. One unit is defined as the amount causing an increase of 1.0 in absorbance at 280 nm per min
additional information
-
with pepsinogen B
additional information
-
milk clotting activity examined
additional information
-
modified Anson test
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
2
-
with haemoglobin
pH RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
1 - 5.5
-
hemoglobin, pH 1: about 50% of maximum activity, pH 5.5: about 10% of maximum activity
2 - 3.4
-
-
2.5 - 5
-
pH 2.5: about 20% of maximal activity, pH 3.0: about 70% of maximal activity, pH 4.0: about 50% of maximal activity
additional information
-
milk clotting activity below pH 6.6
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
35.5
-
assay at
37
-
with haemoglobin
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
2 - 57
-
haemoglobin, 2C: about 55% of maximum activity, 57C: about 30% of maximum activity, Q10 for milk clotting activity
20 - 55
-
20C: about 35% of maximal activity, 50C: about 60% of maximal activity, 55C: about 25% of maximal activity
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
39000
-
SDS-PAGE
95817
40000
-
gel filtration
95816
40000
-
SDS-PAGE, pepsinogen B
95817
57200
-
pepsinogen B, gel filtration, 57200
95814
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
?
-
x * 39000, SDS-PAGE
?
-
N-terminal amino acid sequence reported
?
-
amino acid analysis
?
-
x * 41000, pepsinogen, SDS-PAGE, x * 36000, pepsin B, SDS-PAGE
monomer
-
1 * 31000, SDS-PAGE
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
proteolytic modification
-
-
proteolytic modification
-
-
proteolytic modification
-
-
proteolytic modification
-
pepssinogen B is proteolytically activated in the gastric tract, first cleavage site is Met16-Glu17, convertion at pH 5.5, not at pH 2.0
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
4 - 6.9
-
room temperature, pepsin is stable
668808
6
-
room temperature, 30 min, stable below
679335
6.2
-
30C, unstable
95816
7
-
room temperature, 30 min, about 20% loss of activity
679335
8
-
room temperature, 30 min, about 75% loss of activity
679335
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
30
-
pH 6.2, unstable
95816
40
-
15 min, stable below
679335
50
-
15 min, about 50% loss of activity
679335
60
-
15 min, about 85% loss of activity
679335
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
native pepsinogen by gel filtration and anion exchange chromatography to homogeneity
-
pepsinogen B
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression in Saccharomyces cerevisiae
Q2AB25
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
F219S
Q2AB25
mutant exhibits broad activity against various peptides, with retention of high activity against peptides with Gly at P2
Y13A
Q2AB25
mutant shows new hydrolytic activity against several peptides, whereas the activity against peptides with Gly at P2 is decreased significantly. The newly obtained activity of the Tyr13Ala mutant is low
Y13A/F219S
Q2AB25
mutant demonstrats general proteolytic activity, hydrolyzing various types of peptides very efficiently, although activity against peptides with Gly at P2 is decreased. The activity against typical peptides, such as KPAEFARL, KPAEFLRL, and KPGEFARL, is increased about 40times by the double mutation. The extent being much higher than that with single mutations