SI

Protein identityUniProt · HPA

UniProt accession

P14410

Gene

SI

Ensembl

ENSG00000090402

Chromosome

3

Canonical length

1827 aa

Protein class

Disease related genes, Enzymes, FDA approved drug targets, Human disease related genes, Metabolic proteins, Plasma proteins, Predicted membrane proteins

OverviewNCBI Gene

This gene encodes a sucrase-isomaltase enzyme that is expressed in the intestinal brush border. The encoded protein is synthesized as a precursor protein that is cleaved by pancreatic proteases into two enzymatic subunits sucrase and isomaltase. These two subunits heterodimerize to form the sucrose-isomaltase complex. This complex is essential for the digestion of dietary carbohydrates including starch, sucrose and isomaltose. Mutations in this gene are the cause of congenital sucrase-isomaltase deficiency.[provided by RefSeq, Apr 2010]

Canonical amino-acid sequenceUniProt

1827 residues, UniProt reviewed canonical sequence.

>P14410|SI
     1  MARKKFSGLE ISLIVLFVIV TIIAIALIVV LATKTPAVDE ISDSTSTPAT TRVTTNPSDS
    61  GKCPNVLNDP VNVRINCIPE QFPTEGICAQ RGCCWRPWND SLIPWCFFVD NHGYNVQDMT
   121  TTSIGVEAKL NRIPSPTLFG NDINSVLFTT QNQTPNRFRF KITDPNNRRY EVPHQYVKEF
   181  TGPTVSDTLY DVKVAQNPFS IQVIRKSNGK TLFDTSIGPL VYSDQYLQIS TRLPSDYIYG
   241  IGEQVHKRFR HDLSWKTWPI FTRDQLPGDN NNNLYGHQTF FMCIEDTSGK SFGVFLMNSN
   301  AMEIFIQPTP IVTYRVTGGI LDFYILLGDT PEQVVQQYQQ LVGLPAMPAY WNLGFQLSRW
   361  NYKSLDVVKE VVRRNREAGI PFDTQVTDID YMEDKKDFTY DQVAFNGLPQ FVQDLHDHGQ
   421  KYVIILDPAI SIGRRANGTT YATYERGNTQ HVWINESDGS TPIIGEVWPG LTVYPDFTNP
   481  NCIDWWANEC SIFHQEVQYD GLWIDMNEVS SFIQGSTKGC NVNKLNYPPF TPDILDKLMY
   541  SKTICMDAVQ NWGKQYDVHS LYGYSMAIAT EQAVQKVFPN KRSFILTRST FAGSGRHAAH
   601  WLGDNTASWE QMEWSITGML EFSLFGIPLV GADICGFVAE TTEELCRRWM QLGAFYPFSR
   661  NHNSDGYEHQ DPAFFGQNSL LVKSSRQYLT IRYTLLPFLY TLFYKAHVFG ETVARPVLHE
   721  FYEDTNSWIE DTEFLWGPAL LITPVLKQGA DTVSAYIPDA IWYDYESGAK RPWRKQRVDM
   781  YLPADKIGLH LRGGYIIPIQ EPDVTTTASR KNPLGLIVAL GENNTAKGDF FWDDGETKDT
   841  IQNGNYILYT FSVSNNTLDI VCTHSSYQEG TTLAFQTVKI LGLTDSVTEV RVAENNQPMN
   901  AHSNFTYDAS NQVLLIADLK LNLGRNFSVQ WNQIFSENER FNCYPDADLA TEQKCTQRGC
   961  VWRTGSSLSK APECYFPRQD NSYSVNSARY SSMGITADLQ LNTANARIKL PSDPISTLRV
  1021  EVKYHKNDML QFKIYDPQKK RYEVPVPLNI PTTPISTYED RLYDVEIKEN PFGIQIRRRS
  1081  SGRVIWDSWL PGFAFNDQFI QISTRLPSEY IYGFGEVEHT AFKRDLNWNT WGMFTRDQPP
  1141  GYKLNSYGFH PYYMALEEEG NAHGVFLLNS NAMDVTFQPT PALTYRTVGG ILDFYMFLGP
  1201  TPEVATKQYH EVIGHPVMPA YWALGFQLCR YGYANTSEVR ELYDAMVAAN IPYDVQYTDI
  1261  DYMERQLDFT IGEAFQDLPQ FVDKIRGEGM RYIIILDPAI SGNETKTYPA FERGQQNDVF
  1321  VKWPNTNDIC WAKVWPDLPN ITIDKTLTED EAVNASRAHV AFPDFFRTST AEWWAREIVD
  1381  FYNEKMKFDG LWIDMNEPSS FVNGTTTNQC RNDELNYPPY FPELTKRTDG LHFRTICMEA
  1441  EQILSDGTSV LHYDVHNLYG WSQMKPTHDA LQKTTGKRGI VISRSTYPTS GRWGGHWLGD
  1501  NYARWDNMDK SIIGMMEFSL FGMSYTGADI CGFFNNSEYH LCTRWMQLGA FYPYSRNHNI
  1561  ANTRRQDPAS WNETFAEMSR NILNIRYTLL PYFYTQMHEI HANGGTVIRP LLHEFFDEKP
  1621  TWDIFKQFLW GPAFMVTPVL EPYVQTVNAY VPNARWFDYH TGKDIGVRGQ FQTFNASYDT
  1681  INLHVRGGHI LPCQEPAQNT FYSRQKHMKL IVAADDNQMA QGSLFWDDGE SIDTYERDLY
  1741  LSVQFNLNQT TLTSTILKRG YINKSETRLG SLHVWGKGTT PVNAVTLTYN GNKNSLPFNE
  1801  DTTNMILRID LTTHNVTLEE PIEINWS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SI can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability

Cell surface

Secreted

No

Transmembrane segments

1

Mean surface accessibility (rSASA)

0.19

Highest tissue expression

513 nTPM

Expression across tissuesHPA

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about SI.

Disease | AllUniProt

Conditions SI is implicated in, by any mechanism.

• Congenital sucrase-isomaltase deficiency (CSID) MIM:222900

Disease | GeneticClinVar

163 pathogenic / likely-pathogenic of 1,694 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

• Sucrase-isomaltase deficiency
• SI-related disorder
• Inborn genetic diseases
• Congenital sucrose-isomaltase deficiency

Disease | ImmuneIEDB

Conditions an epitope on SI was assayed in.

• Crohn's disease B cell
• ulcerative colitis B cell

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)

1.04

gnomAD pLI

0

gnomAD missense Z

-1.08

DepMap mean gene effect

0.11

DepMap dependency class

none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

• polysaccharide digestion
• sucrose catabolic process

Molecular functions

• alpha-1,4-glucosidase activity
• carbohydrate binding
• oligo-1,6-glucosidase activity
• sucrose alpha-glucosidase activity

Cellular components

• apical plasma membrane
• brush border
• extracellular exosome
• Golgi apparatus
• plasma membrane

Protein domainsUniProt · Pfam · InterPro

• Glycoside hydrolase family 31, TIM barrel domain
• P-type trefoil domain
• Galactose mutarotase-like domain superfamily
• Glycosyl hydrolase, all-beta
• Glycoside hydrolase superfamily
• P-type trefoil, conserved site
• Glycoside hydrolase family 31, N-terminal domain
• Glycosyl hydrolases family 31, active site
• Glycosyl hydrolases family 31, conserved site
• P-type trefoil domain superfamily
• Glycosyl hydrolase family 31, C-terminal domain
• Trefoil (P-type) domain
• Glycosyl hydrolases family 31 TIM-barrel domain
• Glycosyl hydrolase 31 N-terminal galactose mutarotase-like domain
• Glycosyl hydrolase family 31 C-terminal domain

KeywordsUniProt

• Cell membrane
• Disulfide bond
• Glycoprotein
• Glycosidase
• Hydrolase
• Membrane
• Multifunctional enzyme
• Phosphoprotein
• Repeat
• Signal-anchor
• Sulfation
• Transmembrane
• Transmembrane helix