Biosynthesis of intestinal microvillar proteins. Processing of aminopeptidase N by microsomal membranes
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Biosynthesis of intestinal microvillar proteins. Processing of aminopeptidase N by microsomal membranes. / Danielsen, E M; Norén, Ove; Sjöström, H.
I: Biochemical Journal, Bind 212, Nr. 1, 1983, s. 161-5.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Biosynthesis of intestinal microvillar proteins. Processing of aminopeptidase N by microsomal membranes
AU - Danielsen, E M
AU - Norén, Ove
AU - Sjöström, H
N1 - Keywords: Acetylglucosaminidase; Aminopeptidases; Animals; Antigens, CD13; Cell-Free System; Dogs; Intestine, Small; Intracellular Membranes; Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; Membrane Proteins; Microsomes; Microvilli; Organ Culture Techniques; Peptides; Protein Biosynthesis; Swine
PY - 1983
Y1 - 1983
N2 - The biosynthesis of small-intestinal aminopeptidase N (EC 3.4.11.2) was studied in a cell-free translation system derived from rabbit reticulocytes. When dog pancreatic microsomal fractions were present during translation, most of the aminopeptidase N synthesized was found in a membrane-bound rather than a soluble form, indicating that synthesis of the enzyme takes place on ribosomes attached to the rough endoplasmic reticulum. The microsomal fractions process the Mr-115 000 polypeptide, which is the primary translation product of aminopeptidase N, to a polypeptide of Mr 140 000. This was found to be sensitive to the action of endo-beta-N-acetylglucosaminidase H (EC 3.2.1.96), showing that aminopeptidase N undergoes transmembrane glycosylation during synthesis. The position of the signal sequence in aminopeptidase N was determined by a synchronized translation experiment. It was found that microsomal fractions should be added before about 25% of the polypeptide was synthesized to ensure processing to the high-mannose glycosylated form. This suggests that the signal sequence is situated in the N-terminal part of the aminopeptidase N. The size of the cell-free translation product in the absence of microsomal fractions was found to be similar to that on one of the forms of the enzyme obtained from tunicamycin-treated organ-cultured intestinal explants.
AB - The biosynthesis of small-intestinal aminopeptidase N (EC 3.4.11.2) was studied in a cell-free translation system derived from rabbit reticulocytes. When dog pancreatic microsomal fractions were present during translation, most of the aminopeptidase N synthesized was found in a membrane-bound rather than a soluble form, indicating that synthesis of the enzyme takes place on ribosomes attached to the rough endoplasmic reticulum. The microsomal fractions process the Mr-115 000 polypeptide, which is the primary translation product of aminopeptidase N, to a polypeptide of Mr 140 000. This was found to be sensitive to the action of endo-beta-N-acetylglucosaminidase H (EC 3.2.1.96), showing that aminopeptidase N undergoes transmembrane glycosylation during synthesis. The position of the signal sequence in aminopeptidase N was determined by a synchronized translation experiment. It was found that microsomal fractions should be added before about 25% of the polypeptide was synthesized to ensure processing to the high-mannose glycosylated form. This suggests that the signal sequence is situated in the N-terminal part of the aminopeptidase N. The size of the cell-free translation product in the absence of microsomal fractions was found to be similar to that on one of the forms of the enzyme obtained from tunicamycin-treated organ-cultured intestinal explants.
M3 - Journal article
C2 - 6135417
VL - 212
SP - 161
EP - 165
JO - Biochemical Journal
JF - Biochemical Journal
SN - 0264-6021
IS - 1
ER -
ID: 9881358