Toggle navigation
SMPDB
Browse SMPDB
Pathways
Table of Primary Pathways
Compounds
Proteins
Search
TextQuery Search Instructions
SMP-MAP Advanced Search
ChemQuery Structure Search
Molecular Weight Search
Sequence Search
About
About SMPDB
Release Notes
Citing SMPDB
Statistics
Other Databases
Pathway Legend
Pathway Category Definitions
PathWhiz
Downloads
Contact Us
Quantitative metabolomics services for biomarker discovery and validation.
Specializing in ready to use metabolomics kits.
Your source for quantitative metabolomics technologies and bioinformatics.
Loading Pathway...
Error: Pathway image not found.
Glutaminase
Lactose
permease
L-lactate
permease
Beta-
galactosidase
Lactulose
Ammonium
D-Glucose
Methane
L-Lactic acid
H
+
NH
3
Lactulose
Lactulose
H
2
O
H
2
O
L-Lactic acid
Methane
H
+
NH
3
H
2
O
D-Galactose
H
+
Hydroxide
H
2
O
NH
3
Hydroxide
L-Lactic acid
Methane
H
+
Lactate
L-Glutamine
H
2
O
L-Glutamic acid
Magnesium
Sodium
Excretion
Glycolysis
(Escherichia
coli (strain
K12))
Protein
Synthesis
(Escherichia
coli (strain
K12))
Colonic bacterial cell
1. Lactulose is metabolized
to volatile acids, mainly
lactic acid, but acetic acid
and formic acid can also be
formed. Gases such as
methane and hydrogen are
also formed
Acidic pH
2. Lactic acid in the
intestine increases the pH
and osmotic pressure, thus
stimulating peristalsis
4. Metabolism of lactulose
increases intraluminal gas
which contribute to colon
distension and peristalsis
3. Due to the high osmotic
pressure in the colon lumen,
water is drawn in. This
further contributes to colon
distension, softening of the
stool and peristalsis
5. The acidic environment
leads to the conversion of
ammonia to ammonium.
Ammonium can not cross cell
membranes, and therefore is
excreted in faeces
7. Ammonia is used as a
nitrogen source in protein
synthesis
Urease-producing bacteria
8. The acidic pH destroys
urease-producing bacteria
involved in the production
of ammonia, reducing
intestinal production of
ammonia
6. Colonic ammonia can be
taken up and utilized by
bacteria
Intestinal epithelial cell
9. Lactulose can also
decrease glutaminase
activity, preventing the
production of ammonia
GLS
lacY
lldP
lacZ
Lactulose
Ammonium
D-Glucose
Methane
L-Lactic acid
Hydrogen
Ammonia
Lactulose
Lactulose
Water
Water
L-Lactic acid
Methane
Hydrogen
Ammonia
Water
D-Galactose
Hydrogen Ion
Hydroxide
Water
Ammonia
Hydroxide
L-Lactic acid
Methane
Hydrogen
Lactate
L-Glutamine
Water
L-Glutamic acid
Excretion
Glycolysis
(Escherichia
coli (strain
K12))
Protein
Synthesis
(Escherichia
coli (strain
K12))