KEGG   PATHWAY: ko04974Help
Entry
ko04974                     Pathway                                
Name
Protein digestion and absorption
Description
Protein is a dietary component essential for nutritional homeostasis in humans. Normally, ingested protein undergoes a complex series of degradative processes following the action of gastric, pancreatic and small intestinal enzymes. The result of this proteolytic activity is a mixture of amino acids and small peptides. Amino acids (AAs) are transported into the enterocyte (intestinal epithelial cell) by a variety of AA transporters that are specific for cationic (basic) AA, neutral AA, and anionic (acidic) AA. Small peptides are absorbed into enterocytes by the PEPT1 transporter. Inside enterocytes peptides are hydrolyzed, and the resulting amino acids are released together with those absorbed by AA transporters into blood via multiple, basolateral, AA transporters. Hydrolysis-resistant peptides, however, are transported out of the cells by a basolateral peptide transporter that has not been identified molecularly.
Class
Organismal Systems; Digestive system
BRITE hierarchy
Pathway map
Protein digestion and absorption
ko04974

All organismsOrtholog table
Disease
H00843  
Hartnup disorder
H00899  
Lysinuric protein intolerance (LPI)
H00901  
Cystinuria
H00905  
Iminoglycinuria
H00911  
Dicarboxylic aminoaciduria
H00933  
Hereditary pancreatitis
H01304  
Hyperglycinuria
Other DBs
Orthology
K06002  
pepsin A [EC:3.4.23.1]
K01312  
trypsin [EC:3.4.21.4]
K09632  
chymotrypsin-like protease [EC:3.4.21.-]
K01346  
pancreatic elastase II [EC:3.4.21.71]
K01345  
pancreatic endopeptidase E [EC:3.4.21.70]
K08779  
carboxypeptidase A1 [EC:3.4.17.1]
K01298  
carboxypeptidase A2 [EC:3.4.17.15]
K08780  
carboxypeptidase A3 [EC:3.4.17.1]
K01291  
carboxypeptidase B [EC:3.4.17.2]
K01300  
carboxypeptidase B2 [EC:3.4.17.20]
K12040  
solute carrier family 9 (sodium/hydrogen exchanger), member 3
K14206  
solute carrier family 15 (oligopeptide transporter), member 1
K01539  
sodium/potassium-transporting ATPase subunit alpha [EC:3.6.3.9]
K01540  
sodium/potassium-transporting ATPase subunit beta
K01538  
sodium/potassium-transporting ATPase subunit gamma (FXYD domain-containing ion transport regulator 2)
K04945  
potassium intermediate/small conductance calcium-activated channel subfamily N member 4
K04916  
potassium channel subfamily K member 5
K04897  
potassium voltage-gated channel Isk-related subfamily E member 3
K04926  
potassium voltage-gated channel KQT-like subfamily member 1
K05006  
potassium inwardly-rectifying channel subfamily J member 13
K14207  
solute carrier family 38 (sodium-coupled neutral amino acid transporter), member 2
K01389  
neprilysin [EC:3.4.24.11]
K01395  
meprin A, alpha [EC:3.4.24.18]
K08606  
meprin A, beta [EC:3.4.24.18]
K09708  
angiotensin-converting enzyme 2 [EC:3.4.17.23]
K01285  
lysosomal Pro-X carboxypeptidase [EC:3.4.16.2]
K01278  
dipeptidyl-peptidase 4 [EC:3.4.14.5]
K14208  
Xaa-Pro aminopeptidase 2 [EC:3.4.11.9]
K05612  
solute carrier family 1 (neuronal/epithelial high affinity glutamate transporter), member 1
K05616  
solute carrier family 1 (neutral amino acid transporter), member 5
K05849  
solute carrier family 8 (sodium/calcium exchanger)
K05334  
solute carrier family 6 (neurotransmitter transporter) member 19
K06519  
solute carrier family 3, member 2
K13781  
solute carrier family 7 (L-type amino acid transporter), member 8
K08187  
MFS transporter, MCP family, solute carrier family 16 (monocarboxylic acid transporters), member 10
K14210  
solute carrier family 3 (neutral and basic amino acid transporter), member 1
K13868  
solute carrier family 7 (L-type amino acid transporter), member 9
K13867  
solute carrier family 7 (L-type amino acid transporter), member 7
K14211  
elastin
K06236  
collagen, type I/II/III/V/XI/XXIV/XXVII, alpha
K06237  
collagen, type IV, alpha
K06238  
collagen, type VI, alpha
K16628  
collagen, type VII, alpha
K08131  
collagen, type IX, alpha
K08132  
collagen, type XII, alpha
K16617  
collagen, type XIII, alpha
K08133  
collagen, type XIV, alpha
K08135  
collagen, type XV, alpha
K07603  
collagen, type XVII, alpha
K06823  
collagen, type XVIII, alpha
K16629  
collagen, type XXI, alpha
K16630  
collagen, type XXII, alpha
Compound
C00011  
CO2
C00014  
NH3
C00025  
L-Glutamate
C00033  
Acetate
C00037  
Glycine
C00041  
L-Alanine
C00047  
L-Lysine
C00049  
L-Aspartate
C00062  
L-Arginine
C00064  
L-Glutamine
C00065  
L-Serine
C00073  
L-Methionine
C00076  
Calcium cation
C00078  
L-Tryptophan
C00079  
L-Phenylalanine
C00080  
H+
C00082  
L-Tyrosine
C00097  
L-Cysteine
C00099  
beta-Alanine
C00123  
L-Leucine
C00134  
Putrescine
C00135  
L-Histidine
C00146  
Phenol
C00148  
L-Proline
C00152  
L-Asparagine
C00163  
Propanoate
C00183  
L-Valine
C00188  
L-Threonine
C00238  
Potassium cation
C00246  
Butanoic acid
C00282  
Hydrogen
C00388  
Histamine
C00407  
L-Isoleucine
C00463  
Indole
C00483  
Tyramine
C00491  
L-Cystine
C01327  
Hydrochloric acid
C01330  
Sodium cation
C01438  
Methane
C01468  
4-Cresol
C01672  
Cadaverine
C01746  
Piperidine
C02632  
2-Methylpropanoate
C05996  
Branched chain fatty acid
C08262  
3-Methylbutanoic acid
C16138  
L-Pyrrolysine
C18319  
2-Methylbutyrate
Reference
  Authors
Broer S
  Title
Amino acid transport across mammalian intestinal and renal epithelia.
  Journal
Physiol Rev 88:249-86 (2008)
Reference
  Authors
Palacin M, Nunes V, Font-Llitjos M, Jimenez-Vidal M, Fort J, Gasol E, Pineda M, Feliubadalo L, Chillaron J, Zorzano A
  Title
The genetics of heteromeric amino acid transporters.
  Journal
Physiology (Bethesda) 20:112-24 (2005)
Reference
  Authors
Goodman BE
  Title
Insights into digestion and absorption of major nutrients in humans.
  Journal
Adv Physiol Educ 34:44-53 (2010)
Reference
  Authors
Wagner CA, Lang F, Broer S
  Title
Function and structure of heterodimeric amino acid transporters.
  Journal
Am J Physiol Cell Physiol 281:C1077-93 (2001)
Reference
  Authors
Broer S
  Title
Apical transporters for neutral amino acids: physiology and pathophysiology.
  Journal
Physiology (Bethesda) 23:95-103 (2008)
Reference
PMID:9687539
  Authors
Wu G
  Title
Intestinal mucosal amino acid catabolism.
  Journal
J Nutr 128:1249-52 (1998)
Reference
  Authors
Daniel H
  Title
Molecular and integrative physiology of intestinal peptide transport.
  Journal
Annu Rev Physiol 66:361-84 (2004)
Reference
  Authors
Rubio-Aliaga I, Daniel H
  Title
Mammalian peptide transporters as targets for drug delivery.
  Journal
Trends Pharmacol Sci 23:434-40 (2002)
Reference
PMID:7937532
  Authors
Bai JP
  Title
Distribution of brush-border membrane peptidases along the rat intestine.
  Journal
Pharm Res 11:897-900 (1994)
Reference
  Authors
Guarner F, Malagelada JR
  Title
Gut flora in health and disease.
  Journal
Lancet 361:512-9 (2003)
Reference
  Authors
Smith EA, Macfarlane GT
  Title
Dissimilatory amino Acid metabolism in human colonic bacteria.
  Journal
Anaerobe 3:327-37 (1997)
Reference
  Authors
Schepers E, Glorieux G, Vanholder R
  Title
The gut: the forgotten organ in uremia?
  Journal
Blood Purif 29:130-6 (2010)
Reference
  Authors
John H.Cummings
  Title
The large intestine in nutrition and disease
  Journal
Institut Danone
Reference
  Authors
Heitzmann D, Warth R
  Title
Physiology and pathophysiology of potassium channels in gastrointestinal epithelia.
  Journal
Physiol Rev 88:1119-82 (2008)
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