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lactase phlorizin hydrolase; lactase glycosylceramidase; lactase (LCT, LPH)
Function:
- LCT splits lactose in the small intestine
lactose + H2O D-galactose + D-glucose
Glycosyl-N-acylsphingosine + H2O
N-acylsphingosine + a sugar
Structure:
- exhibits 4 regions (I-IV) of internal homology; thus LPH might have evolved by two cycles of partial gene duplication
- belongs to the glycosyl hydrolase 1 family
Compartment:
- apical cell membrane
- brush border
Expression:
- intestine
- developmental down-regulation of lactase activity during childhood or early adulthood
- down-regulation of lactase activity operates at the transcriptional level & it is associated with a noncoding variation in the MCM6 gene, located in the upstream vicinity of LCT
Pathology:
- defects in LCT are the cause of congenital lactase deficiency
- developmental down-regulation of lactase activity during childhood or early adulthood results in lactose intolerance
Pharmacology:
- oral formulation used in treatment of lactase deficiency
Related
lactase
LCT gene mutation
Specific
Lactase Phlorizin Hydrolase Oral
General
glucosidase
membrane protein
metabolic agent (metabolic modifier)
Properties
SIZE: entity length = 1927 aa
MW = 219 kD
COMPARTMENT: cellular membrane
MOTIF: signal sequence {1-19}
4 X approximate repeats {87-1841}
MOTIF: consensus repeat {87-172}
consensus repeat {363-848}
consensus repeat {884-1365}
glutamate residue {E1065}
glutamate residue {E1273}
Tyr phosphorylation site {Y1303}
Tyr phosphorylation site {Y1313}
consensus repeat {1370-1841}
glutamate residue {E1538}
glutamate residue {E1749}
transmembrane domain {1883-1901}
Database Correlations
OMIM correlations
MORBIDMAP 603202
UniProt P09848
Pfam PF00232
Entrez Gene 3938
Kegg hsa:3938
ENZYME correlations
References
- UniProt :accession P09848
- GeneReviews
https://www.genecards.org/cgi-bin/carddisp.pl?gene=LCT
- Wikipedia; Note: lactase entry
http://en.wikipedia.org/wiki/lactase