Biosynthesis of intestinal microvillar proteins. Pulse-chase labelling studies on aminopeptidase N and sucrase-isomaltase
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Biosynthesis of intestinal microvillar proteins. Pulse-chase labelling studies on aminopeptidase N and sucrase-isomaltase. / Danielsen, Erik Michael.
I: Biochemical Journal, Bind 204, Nr. 3, 1982, s. 639-45.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Biosynthesis of intestinal microvillar proteins. Pulse-chase labelling studies on aminopeptidase N and sucrase-isomaltase
AU - Danielsen, Erik Michael
N1 - Keywords: Acetylglucosaminidase; Aminopeptidases; Animals; Antigens, CD13; Calcium; Electrophoresis, Polyacrylamide Gel; Immunoelectrophoresis; Intestine, Small; Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; Microvilli; Multienzyme Complexes; Organ Culture Techniques; Sucrase-Isomaltase Complex; Swine
PY - 1982
Y1 - 1982
N2 - The biogenesis of two microvillar enzymes, aminopeptidase N (EC 3.4.11.2) and sucrase (EC 3.2.1.48)-isomaltase (EC 3.2.1.10), was studied by pulse-chase labelling of pig small-intestinal explants kept in organ culture. Both enzymes became inserted into the membrane during or immediately after polypeptide synthesis, indicating that translation takes place on ribosomes attached to the rough endoplasmic reticulum. The earliest detectable forms of aminopeptidase and sucrase-isomaltase were polypeptides of Mr 140 000 and 240 000 respectively. These polypeptides were susceptible to treatment with endo-beta-N-acetylglucosaminidiase H (EC 3.2.1.96), suggesting that the microvillar enzymes during or immediately after completion of protein synthesis become glycosylated with a 'high-mannose' oligosaccharide structure similarly to other plasma-membrane and secretory proteins. After 20--40 min or 60--90 min of chase, respectively, aminopeptidase N and sucrase-isomaltase were reglycosylated to give the polypeptides of Mr 166 000 (aminopeptidase N) and 265 000 (sucrase-isomaltase). These were expressed at the microvillar membrane after 60--90 min. During the entire process of synthesis and transport to the microvillar membrane the enzymes were bound to membranes, indicating that the biogenesis of aminopeptidase N and sucrase-isomaltase occurs in accordance with the membrane flow hypothesis.
AB - The biogenesis of two microvillar enzymes, aminopeptidase N (EC 3.4.11.2) and sucrase (EC 3.2.1.48)-isomaltase (EC 3.2.1.10), was studied by pulse-chase labelling of pig small-intestinal explants kept in organ culture. Both enzymes became inserted into the membrane during or immediately after polypeptide synthesis, indicating that translation takes place on ribosomes attached to the rough endoplasmic reticulum. The earliest detectable forms of aminopeptidase and sucrase-isomaltase were polypeptides of Mr 140 000 and 240 000 respectively. These polypeptides were susceptible to treatment with endo-beta-N-acetylglucosaminidiase H (EC 3.2.1.96), suggesting that the microvillar enzymes during or immediately after completion of protein synthesis become glycosylated with a 'high-mannose' oligosaccharide structure similarly to other plasma-membrane and secretory proteins. After 20--40 min or 60--90 min of chase, respectively, aminopeptidase N and sucrase-isomaltase were reglycosylated to give the polypeptides of Mr 166 000 (aminopeptidase N) and 265 000 (sucrase-isomaltase). These were expressed at the microvillar membrane after 60--90 min. During the entire process of synthesis and transport to the microvillar membrane the enzymes were bound to membranes, indicating that the biogenesis of aminopeptidase N and sucrase-isomaltase occurs in accordance with the membrane flow hypothesis.
M3 - Journal article
C2 - 6127070
VL - 204
SP - 639
EP - 645
JO - Biochemical Journal
JF - Biochemical Journal
SN - 0264-6021
IS - 3
ER -
ID: 13063645