SI Antibody – Rabbit Polyclonal

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]

SI: Plays an important role in the final stage of carbohydrate digestion. Isomaltase activity is specific for both alpha-1,4- and alpha-1,6-oligosaccharides. Defects in SI are the cause of congenital sucrase- isomaltase deficiency (CSID); also known as disaccharide intolerance I. CSID is an autosomal recessive intestinal disorder that is clinically characterized by fermentative diarrhea, abdominal pain, and cramps upon ingestion of sugar. The symptoms are the consequence of absent or drastically reduced enzymatic activities of sucrase and isomaltase. The prevalence of CSID is 0.02 % in individuals of European descent and appears to be much higher in Greenland, Alaskan, and Canadian native people. CSID arises due to post- translational perturbations in the intracellular transport, polarized sorting, aberrant processing, and defective function of SI. Belongs to the glycosyl hydrolase 31 family.

Protein type: Hydrolase; EC 3.2.1.10; Membrane protein, integral; Carbohydrate Metabolism - starch and sucrose; EC 3.2.1.48

Chromosomal Location of Human Ortholog: 3q25.2-q26.2

Cellular Component: Golgi apparatus; apical plasma membrane; integral to membrane; plasma membrane; brush border

Molecular Function: oligo-1,6-glucosidase activity; alpha-glucosidase activity; sucrose alpha-glucosidase activity; carbohydrate binding

Biological Process: polysaccharide digestion; carbohydrate metabolic process; pathogenesis

Disease: Sucrase-isomaltase Deficiency, Congenital