The terminal differentiation of intestinal development occurs during cytodifferentiation and the weaning transition age. Lactase-phlorizin hydrolase (Lact), liver fatty acid binding protein (Fabp1), and sucrase-isomaltase (SI) are well-characterized markers of these transitions. Lact gene expression is spatiotemporally regulated during mammalian gut development. The Zn finger transcription factor family member Gata4 and hepatocyte nuclearfac-1alfa each are indispensable for Lact and Fabp1 expression but both are dispensable for SI gene expression (1). Intestinal and renal epithelial cells are characterized by distinct apical and basolateral membrane domains that are separated by tight junctions and the establishment and maintenance of this polarity depend on specific gene expression and protein targeting to their correct location. One of the protein responsible for correct targeting of proteins is galactic-3, a member of conserved family of lectin proteins. The transport defects in the intestinal brush border Lact in galactin-3 null mutant mice suggest that Lact trafficking involves direct interaction with galactin-3 it transit thru noon-raft-dependent apical transport platform. Deficiency of intestinal lactase, the enzyme required for lactose digestion, can result in symptoms of gastrointestinal malabsorption, or lactose intolerance. Congenital lactase deficiency (CLD) is a cause of disaccharide intolerance and malabsorption characterized by watery diarrhea in infants fed breast milk or lactose-containing formulas. Although the exact cause of CLD is not known, mutations in the coding region of brush border Lact are found to cause CLD in a Finnish study. A mutant Lact (Glycine 1363 was replaced by serine) when expressed in Cos-1 cells resulted in misfolded, enzymatically inactive protein that accumulated in ER. The activity and trafficking is partially restored by expression at permissive temperature (2). Several mutations have been observed in Lactase gene among European populations. A single nucleotide substitution leading to an amino acid change S688 to P in exon 7 and E 1612 to X in exon 12 are found in Italian hypolactasia patients. Five base deletion V565 fsX567 leading to stop codon inexon 6 was found in one and E1612 to X in Exxon 12 was noted in Finnish patents.
In pre weaning rats the intestinal lactase is found in both membrane bound and soluble forms, the distribution and post-translational modifications depend upon hormones, thyroxine and cortisone levels (4). The post natal development of intestine is associated with decrease in particulate Lact activity partly due to proteolysis by luminal proteases, a condition commonly associated with hypolactasia in human (4, 5). Lact is expressed in at least 2 splice forms with apparent MW ranging from 200-240kDa. The Lact has at least 3 “Glycosyl hydrolase family 1” motifs spaced though out the protein. Lact has a single membrane anchor domain near the C-terminal end and has 7 putative asparagines linked glycosylation sites.
The Intestinal lactase-selective antibody was generated against a peptide from the globular domain that is unique to Lactase protein. This epitope is conserved in rat and mouse. The affinity purified mono epitope-specific rabbit polyclonal antibody strongly labels an approximately 200-240kDa intestinal lactase protein in PC-Lact and rat enterocyte cell extracts. The affinity purified anti-Lactase antibody is conjugated to FITC and further purified to remove unconjugated fluorophore and denatured Igs, the FITC conjugated antibody is stabilized for long-term storage. Limited quantities of antigenic blocking peptide for Lact-101AP antibody and western blot positive controls for intestinal lactase in ready-to-use buffer are also available (Please inquire for availability of peptides and western blot positive controls before placing order) . FabGennix Inc. will conjugate its antibodies to other fluorophorescent probes and secondary enzymes at nominal charge. FabGennix Inc. also provides antibodies against many GPCRs, leptin and other obesity related proteins, for a complete listing, please visit www.FabGennix.com.
For research use only, not for diagnostic or therapeutic use.
Citations
Search FabGennix Product Citation Data Base
Search
