Immunoelectrophoretic studies on human small-intestinal brush-border proteins.
The amounts of lactase (beta-D-galactosidase, EC 3.2.1.23), sucrase (sucrose alpha-D-glucohydrolase, EC 3.2.1.48), maltase (alpha-D-glucosidase, EC 3.2.1.20) microvillus aminopeptidase (EC 3.4.11.2) and dipeptidyl peptidase IV (EC 3.4.14.-) in tangentially sectioned biopsies from jejunum were studied by quantitative immunoelectrophoresis and enzymic assays. All enzymes had their maximum activities near the mid-region of the villi and their lowest activities at the bases of the crypts. The ratio between enzyme activity and immunoreactive protein was constant along the villus-crypt axis. This result is consistent with a continuous brush-border-enzyme synthesis as the enterocytes migrate up the villi.
D000626:Aminopeptidases / Q000378:metabolism; D018826:CD13 Antigens; D002462:Cell Membrane / Q000201:enzymology*; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007583:Jejunum / Q000201:enzymology*; D008565:Membrane Proteins / Q000276:immunology*; D008871:Microvilli / Q000201:enzymology* / Q000276:immunology; D013393:Sucrase / Q000378:metabolism; D000520:alpha-Glucosidases / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
D008565:Membrane Proteins; D000520:alpha-Glucosidases; D001616:beta-Galactosidase; D013393:Sucrase; D000626:Aminopeptidases; D018826:CD13 Antigens; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases