title: Peptide hydrolases of the human small intestinal mucosa: identification of six distinct enzymes in the brush border membrane.
abstract: For this investigation highly purified brush border membranes from human small intestine, prepared according to the method described in the preceding paper [1], have been used. Solubilisation of brush border membrane proteins by sodium dodecyl sulphate, Triton X-100 and papain followed by electrophoresis in polyacrylamide gels revealed six distinct peptide hydrolases. These included the enzymes aminopeptidase A (EC 3.4.11.7), dipeptidylpeptidase IV (EC 3.4.14.-), gamma-glutamultranspeptidase (EC 2.3.2.2) and aminopeptidase M (EC 3.4.11.2), which were clearly separable on polyacrylamide gels after solubilisation with Triton X-100 or papain. Activity recovered in the aminopeptidase M peak in the above gel system could be resolved into two distinct peptidases in addition to aminopeptidase M, by SDS-gel-electrophoresis. One of these peptidases was most active towards aliphatic tripeptide (aminopeptidase 1) while the other appeared to be specific for dipeptides (aminopeptidase 2).
mesh_terms: D000626:Aminopeptidases / Q000032:analysis; D002462:Cell Membrane / Q000201:enzymology*; D004150:Dipeptidases / Q000032:analysis; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology*; D008722:Methods; D008871:Microvilli / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000032:analysis* / Q000378:metabolism; D010455:Peptides / Q000378:metabolism
chemical_list: D010455:Peptides; D010447:Peptide Hydrolases; D000626:Aminopeptidases; D004150:Dipeptidases