KEGG   PATHWAY: hsa04973Help
Entry
hsa04973                    Pathway                                

Name
Carbohydrate digestion and absorption - Homo sapiens (human)
Description
Dietary carbohydrate in humans and omnivorous animals is a major nutrient.  The carbohydrates that we ingest vary from the lactose in milk to complex carbohydrates. These carbohydrates are digested to monosaccharides, mostly glucose, galactose and fructose, prior to absorption in the small intestine. Glucose and galactose are initially transported into the enterocyte by SGLT1 located in the apical brush border membrane and then exit through the basolateral membrane by either GLUT2 or exocytosis. In a new model of intestinal glucose absorption, transport by SGLT1 induces rapid insertion and activation of GLUT2 in the brush border membrane by a PKC betaII-dependent mechanism. Moreover, trafficking of apical GLUT2 is rapidly up-regulated by glucose and artificial sweeteners, which act through T1R2 + T1R3/alpha-gustducin to activate PLC-beta2 and PKC-beta II. Fructose is transported separately by the brush border GLUT5 and then released out of the enterocyte into the blood by GLUT2.
Class
Organismal Systems; Digestive system
BRITE hierarchy
Pathway map
Carbohydrate digestion and absorption
hsa04973

All organismsOrtholog table
Disease
H01261  
Congenital glucose-galactose malabsorption (GGM)
Drug
D00025  
Sucrose (JP16/NF)
D00216  
Acarbose (JAN/USAN/INN)
D00625  
Miglitol (JAN/USAN/INN)
D01085  
Saccharin (JP16/NF)
D01665  
Voglibose (JP16/USAN/INN)
D02192  
Saccharin sodium hydrate (JP16)
D02381  
Aspartame (NF/INN)
D05781  
Saccharin calcium (USP)
D08500  
Saccharin sodium
D08836  
Acesulfame potassium (NF)
D08862  
Aspartame acesulfame (NF)
D09779  
Emiglitate (JAN/INN)
Other DBs
Organism
Homo sapiens (human) [GN:hsa]
Gene
278  
AMY1C; amylase, alpha 1C (salivary) [KO:K01176] [EC:3.2.1.1]
279  
AMY2A; amylase, alpha 2A (pancreatic) [KO:K01176] [EC:3.2.1.1]
276  
AMY1A; amylase, alpha 1A (salivary) [KO:K01176] [EC:3.2.1.1]
280  
AMY2B; amylase, alpha 2B (pancreatic) [KO:K01176] [EC:3.2.1.1]
277  
AMY1B; amylase, alpha 1B (salivary) [KO:K01176] [EC:3.2.1.1]
3938  
LCT; lactase [KO:K01229] [EC:3.2.1.62 3.2.1.108]
8972  
MGAM; maltase-glucoamylase (alpha-glucosidase) [KO:K12047] [EC:3.2.1.3 3.2.1.20]
6476  
SI; sucrase-isomaltase (alpha-glucosidase) [KO:K01203] [EC:3.2.1.10 3.2.1.48]
6523  
SLC5A1; solute carrier family 5 (sodium/glucose cotransporter), member 1 [KO:K14158]
476  
ATP1A1; ATPase, Na+/K+ transporting, alpha 1 polypeptide [KO:K01539] [EC:3.6.3.9]
477  
ATP1A2; ATPase, Na+/K+ transporting, alpha 2 polypeptide [KO:K01539] [EC:3.6.3.9]
478  
ATP1A3; ATPase, Na+/K+ transporting, alpha 3 polypeptide [KO:K01539] [EC:3.6.3.9]
480  
ATP1A4; ATPase, Na+/K+ transporting, alpha 4 polypeptide [KO:K01539] [EC:3.6.3.9]
23439  
ATP1B4; ATPase, Na+/K+ transporting, beta 4 polypeptide [KO:K01540]
481  
ATP1B1; ATPase, Na+/K+ transporting, beta 1 polypeptide [KO:K01540]
482  
ATP1B2; ATPase, Na+/K+ transporting, beta 2 polypeptide [KO:K01540]
483  
ATP1B3; ATPase, Na+/K+ transporting, beta 3 polypeptide [KO:K01540]
486  
FXYD2; FXYD domain containing ion transport regulator 2 [KO:K01538]
6514  
SLC2A2; solute carrier family 2 (facilitated glucose transporter), member 2 [KO:K07593]
3101  
HK3; hexokinase 3 (white cell) [KO:K00844] [EC:2.7.1.1]
3098  
HK1; hexokinase 1 [KO:K00844] [EC:2.7.1.1]
3099  
HK2; hexokinase 2 [KO:K00844] [EC:2.7.1.1]
80201  
HKDC1; hexokinase domain containing 1 [KO:K00844] [EC:2.7.1.1]
2542  
SLC37A4; solute carrier family 37 (glucose-6-phosphate transporter), member 4 [KO:K08171]
2538  
G6PC; glucose-6-phosphatase, catalytic subunit [KO:K01084] [EC:3.1.3.9]
57818  
G6PC2; glucose-6-phosphatase, catalytic, 2 [KO:K01084] [EC:3.1.3.9]
92579  
G6PC3; glucose 6 phosphatase, catalytic, 3 [KO:K01084] [EC:3.1.3.9]
6518  
SLC2A5; solute carrier family 2 (facilitated glucose/fructose transporter), member 5 [KO:K08143]
5295  
PIK3R1; phosphoinositide-3-kinase, regulatory subunit 1 (alpha) [KO:K02649]
23533  
PIK3R5; phosphoinositide-3-kinase, regulatory subunit 5 [KO:K02649]
5296  
PIK3R2; phosphoinositide-3-kinase, regulatory subunit 2 (beta) [KO:K02649]
8503  
PIK3R3; phosphoinositide-3-kinase, regulatory subunit 3 (gamma) [KO:K02649]
5290  
PIK3CA; phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha [KO:K00922] [EC:2.7.1.153]
5293  
PIK3CD; phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit delta [KO:K00922] [EC:2.7.1.153]
5291  
PIK3CB; phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit beta [KO:K00922] [EC:2.7.1.153]
5294  
PIK3CG; phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit gamma [KO:K00922] [EC:2.7.1.153]
207  
AKT1; v-akt murine thymoma viral oncogene homolog 1 [KO:K04456] [EC:2.7.11.1]
208  
AKT2; v-akt murine thymoma viral oncogene homolog 2 [KO:K04456] [EC:2.7.11.1]
10000  
AKT3; v-akt murine thymoma viral oncogene homolog 3 [KO:K04456] [EC:2.7.11.1]
776  
CACNA1D; calcium channel, voltage-dependent, L type, alpha 1D subunit [KO:K04851]
80834  
TAS1R2; taste receptor, type 1, member 2 [KO:K04625]
83756  
TAS1R3; taste receptor, type 1, member 3 [KO:K04626]
346562  
GNAT3; guanine nucleotide binding protein, alpha transducing 3 [KO:K04631]
5330  
PLCB2; phospholipase C, beta 2 [KO:K05858] [EC:3.1.4.11]
5579  
PRKCB; protein kinase C, beta [KO:K02677] [EC:2.7.11.13]
Compound
C00011  
CO2
C00031  
D-Glucose
C00033  
Acetate
C00076  
Calcium cation
C00089  
Sucrose
C00092  
D-Glucose 6-phosphate
C00095  
D-Fructose
C00124  
D-Galactose
C00163  
Propanoate
C00165  
Diacylglycerol
C00208  
Maltose
C00238  
Potassium cation
C00243  
Lactose
C00246  
Butanoic acid
C00282  
Hydrogen
C00369  
Starch
C00707  
Xylan
C00714  
Pectin
C00760  
Cellulose
C01330  
Sodium cation
C01355  
Fructan
C01835  
Maltotriose
C02049  
Limit dextrin
C05981  
Phosphatidylinositol-3,4,5-trisphosphate
C08822  
Gum arabic
C12284  
Saccharin sodium anhydrous
C12285  
Sucralose
Reference
  Authors
Drozdowski LA, Thomson AB
  Title
Intestinal sugar transport.
  Journal
World J Gastroenterol 12:1657-70 (2006)
Reference
  Authors
Wright EM, Martin MG, Turk E
  Title
Intestinal absorption in health and disease--sugars.
  Journal
Best Pract Res Clin Gastroenterol 17:943-56 (2003)
Reference
  Authors
Kellett GL, Brot-Laroche E, Mace OJ, Leturque A
  Title
Sugar absorption in the intestine: the role of GLUT2.
  Journal
Annu Rev Nutr 28:35-54 (2008)
Reference
  Authors
Mace OJ, Lister N, Morgan E, Shepherd E, Affleck J, Helliwell P, Bronk JR, Kellett GL, Meredith D, Boyd R, Pieri M, Bailey PD, Pettcrew R, Foley D
  Title
An energy supply network of nutrient absorption coordinated by calcium and T1R taste receptors in rat small intestine.
  Journal
J Physiol 587:195-210 (2009)
Reference
  Authors
Kellett GL, Brot-Laroche E
  Title
Apical GLUT2: a major pathway of intestinal sugar absorption.
  Journal
Diabetes 54:3056-62 (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
Wright EM, Hirayama BA, Loo DF
  Title
Active sugar transport in health and disease.
  Journal
J Intern Med 261:32-43 (2007)
Reference
  Authors
Santer R, Hillebrand G, Steinmann B, Schaub J
  Title
Intestinal glucose transport: evidence for a membrane traffic-based pathway in humans.
  Journal
Gastroenterology 124:34-9 (2003)
Reference
  Authors
Stumpel F, Burcelin R, Jungermann K, Thorens B
  Title
Normal kinetics of intestinal glucose absorption in the absence of GLUT2: evidence for a transport pathway requiring glucose phosphorylation and transfer into the endoplasmic reticulum.
  Journal
Proc Natl Acad Sci U S A 98:11330-5 (2001)
Reference
  Authors
Wright EM, Loo DD, Hirayama BA, Turk E
  Title
Surprising versatility of Na+-glucose cotransporters: SLC5.
  Journal
Physiology (Bethesda) 19:370-6 (2004)
Reference
  Authors
Uldry M, Thorens B
  Title
The SLC2 family of facilitated hexose and polyol transporters.
  Journal
Pflugers Arch 447:480-9 (2004)
Reference
PMID:7555019
  Authors
Van Beers EH, Buller HA, Grand RJ, Einerhand AW, Dekker J
  Title
Intestinal brush border glycohydrolases: structure, function, and development.
  Journal
Crit Rev Biochem Mol Biol 30:197-262 (1995)
Reference
PMID:5089892
  Authors
Marsh MN
  Title
Digestive-absorptive functions of the enterocyte.
  Journal
Ann R Coll Surg Engl 48:356-68 (1971)
Reference
  Authors
Guarner F, Malagelada JR
  Title
Gut flora in health and disease.
  Journal
Lancet 361:512-9 (2003)
Reference
  Authors
Topping DL, Clifton PM
  Title
Short-chain fatty acids and human colonic function: roles of resistant starch and nonstarch polysaccharides.
  Journal
Physiol Rev 81:1031-64 (2001)
KO pathway
 

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