ENTRY       hsa04977                    Pathway
NAME        Vitamin digestion and absorption - Homo sapiens (human)
DESCRIPTION Vitamins are a diverse and chemically unrelated group of organic substances that share a common feature of being essential for normal health and well-being. They catalyze numerous biochemical reactions. Because humans and other mammals cannot synthesize these compounds (except for some synthesis of niacin), they must obtain them from exogenous sources via intestinal absorption. Vitamins are classified based on their solubility in water or fat. Most of the water-soluble vitamins are transported across the small intestinal membrane by carrier-mediated mechanisms, but vitamin B12, cobalamin, is transported by a receptor-mediated mechanism. Intestinal absorption of fat-soluble vitamins requires all of the processes needed for fat absorption. After digestion, these vitamins and the products of pancreatic hydrolysis of triglycerides (TG) are emulsified by bile salts to form mixed micelles which are taken up by intestinal enterocytes and incorporated into chylomicrons (CM). CM are then secreted into the lymphatic system, and finally moves into the plasma.
CLASS       Organismal Systems; Digestive system
PATHWAY_MAP hsa04977  Vitamin digestion and absorption
DBLINKS     GO: 0051180
ORGANISM    Homo sapiens (human) [GN:hsa]
GENE        2694  CBLIF; cobalamin binding intrinsic factor [KO:K14615]
            8029  CUBN; cubilin [KO:K14616]
            55788  LMBRD1; LMBR1 domain containing 1 [KO:K14617]
            25974  MMACHC; metabolism of cobalamin associated C [KO:K14618] [EC:1.16.1.6 2.5.1.151]
            4363  ABCC1; ATP binding cassette subfamily C member 1 [KO:K05665] [EC:7.6.2.3]
            6948  TCN2; transcobalamin 2 [KO:K14619]
            80704  SLC19A3; solute carrier family 19 member 3 [KO:K14610]
            10560  SLC19A2; solute carrier family 19 member 2 [KO:K14610]
            113278  SLC52A3; solute carrier family 52 member 3 [KO:K14620]
            686  BTD; biotinidase [KO:K01435] [EC:3.5.1.12]
            8884  SLC5A6; solute carrier family 5 member 6 [KO:K14386]
            9963  SLC23A1; solute carrier family 23 member 1 [KO:K14611]
            2346  FOLH1; folate hydrolase 1 [KO:K14592] [EC:3.4.17.21]
            113235  SLC46A1; solute carrier family 46 member 1 [KO:K14613]
            6573  SLC19A1; solute carrier family 19 member 1 [KO:K14609]
            949  SCARB1; scavenger receptor class B member 1 [KO:K13885]
            5406  PNLIP; pancreatic lipase [KO:K14073] [EC:3.1.1.3]
            151056  PLB1; phospholipase B1 [KO:K14621] [EC:3.1.1.4 3.1.1.5]
            5948  RBP2; retinol binding protein 2 [KO:K14622]
            158835  AWAT2; acyl-CoA wax alcohol acyltransferase 2 [KO:K11156] [EC:2.3.1.75 2.3.1.76]
            9227  LRAT; lecithin retinol acyltransferase [KO:K00678] [EC:2.3.1.135]
            338  APOB; apolipoprotein B [KO:K14462]
            337  APOA4; apolipoprotein A4 [KO:K08760]
            335  APOA1; apolipoprotein A1 [KO:K08757]
COMPOUND    C00003  NAD+
            C00010  CoA
            C00016  FAD
            C00018  Pyridoxal phosphate
            C00061  FMN
            C00068  Thiamin diphosphate
            C00072  Ascorbate
            C00080  H+
            C00120  Biotin
            C00153  Nicotinamide
            C00162  Fatty acid
            C00187  Cholesterol
            C00250  Pyridoxal
            C00255  Riboflavin
            C00376  Retinal
            C00378  Thiamine
            C00422  Triacylglycerol
            C00473  Retinol
            C00504  Folate
            C00534  Pyridoxamine
            C00647  Pyridoxamine phosphate
            C00681  1-Acyl-sn-glycerol 3-phosphate
            C00828  Menaquinone
            C00864  Pantothenate
            C01330  Sodium cation
            C01558  Bile salt
            C01885  1-Acylglycerol
            C02059  Phylloquinone
            C02075  Retinyl ester
            C02094  beta-Carotene
            C02112  2-Acylglycerol
            C02477  alpha-Tocopherol
            C02530  Cholesterol ester
            C05377  Menadione
            C05443  Vitamin D3
            C05552  Biocytin
            C05776  Vitamin B12
            C12981  dl-alpha-Tocopherol nicotinate
            C13202  alpha-Tocopherol acetate
REFERENCE   PMID:16462170
  AUTHORS   Said HM, Mohammed ZM
  TITLE     Intestinal absorption of water-soluble vitamins: an update.
  JOURNAL   Curr Opin Gastroenterol 22:140-6 (2006)
            DOI:10.1097/01.mog.0000203870.22706.52
REFERENCE   PMID:14642860
  AUTHORS   Basu TK, Donaldson D
  TITLE     Intestinal absorption in health and disease: micronutrients.
  JOURNAL   Best Pract Res Clin Gastroenterol 17:957-79 (2003)
            DOI:10.1016/S1521-6918(03)00084-2
REFERENCE   PMID:14977409
  AUTHORS   Said HM
  TITLE     Recent advances in carrier-mediated intestinal absorption of water-soluble vitamins.
  JOURNAL   Annu Rev Physiol 66:419-46 (2004)
            DOI:10.1146/annurev.physiol.66.032102.144611
REFERENCE   PMID:16206251
  AUTHORS   Reidling JC, Nabokina SM, Balamurugan K, Said HM
  TITLE     Developmental maturation of intestinal and renal thiamin uptake: studies in wild-type and transgenic mice carrying human THTR-1 and 2 promoters.
  JOURNAL   J Cell Physiol 206:371-7 (2006)
            DOI:10.1002/jcp.20492
REFERENCE   PMID:20724488
  AUTHORS   Fujimura M, Yamamoto S, Murata T, Yasujima T, Inoue K, Ohta KY, Yuasa H
  TITLE     Functional characteristics of the human ortholog of riboflavin transporter 2 and riboflavin-responsive expression of its rat ortholog in the small intestine indicate its involvement in riboflavin absorption.
  JOURNAL   J Nutr 140:1722-7 (2010)
            DOI:10.3945/jn.110.128330
REFERENCE   PMID:19056639
  AUTHORS   Said HM
  TITLE     Cell and molecular aspects of human intestinal biotin absorption.
  JOURNAL   J Nutr 139:158-62 (2009)
            DOI:10.3945/jn.108.092023
REFERENCE   PMID:20185591
  AUTHORS   Green R
  TITLE     Ins and outs of cellular cobalamin transport.
  JOURNAL   Blood 115:1476-7 (2010)
            DOI:10.1182/blood-2009-12-254037
REFERENCE   PMID:19173758
  AUTHORS   Zhao R, Matherly LH, Goldman ID
  TITLE     Membrane transporters and folate homeostasis: intestinal absorption and transport into systemic compartments and tissues.
  JOURNAL   Expert Rev Mol Med 11:e4 (2009)
            DOI:10.1017/S1462399409000969
REFERENCE   PMID:11984580
  AUTHORS   Hediger MA
  TITLE     New view at C.
  JOURNAL   Nat Med 8:445-6 (2002)
            DOI:10.1038/nm0502-445
REFERENCE   PMID:11340090
  AUTHORS   Harrison EH, Hussain MM
  TITLE     Mechanisms involved in the intestinal digestion and absorption of dietary vitamin A.
  JOURNAL   J Nutr 131:1405-8 (2001)
            DOI:10.1093/jn/131.5.1405
REFERENCE   PMID:16688755
  AUTHORS   Blomhoff R, Blomhoff HK.
  TITLE     Overview of retinoid metabolism and function.
  JOURNAL   J Neurobiol 66:606-30 (2006)
            DOI:10.1002/neu.20242
REFERENCE   PMID:20166147
  AUTHORS   Lemaire-Ewing S, Desrumaux C, Neel D, Lagrost L
  TITLE     Vitamin E transport, membrane incorporation and cell metabolism: Is alpha-tocopherol in lipid rafts an oar in the lifeboat?
  JOURNAL   Mol Nutr Food Res 54:631-40 (2010)
            DOI:10.1002/mnfr.200900445
REFERENCE   PMID:18841274
  AUTHORS   Shearer MJ, Newman P
  TITLE     Metabolism and cell biology of vitamin K.
  JOURNAL   Thromb Haemost 100:530-47 (2008)
            DOI:10.1160/TH08-03-0147
REL_PATHWAY hsa04142  Lysosome
            hsa04144  Endocytosis
            hsa04975  Fat digestion and absorption
            hsa04976  Bile secretion
KO_PATHWAY  ko04977
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