کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2187366 1096113 2008 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Isolation of an Isoenzyme of Human Glutaminyl Cyclase: Retention in the Golgi Complex Suggests Involvement in the Protein Maturation Machinery
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Isolation of an Isoenzyme of Human Glutaminyl Cyclase: Retention in the Golgi Complex Suggests Involvement in the Protein Maturation Machinery
چکیده انگلیسی

Mammalian glutaminyl cyclase isoenzymes (isoQCs) were identified. The analysis of the primary structure of human isoQC (h-isoQC) revealed conservation of the zinc-binding motif of the human QC (hQC). In contrast to hQC, h-isoQC carries an N-terminal signal anchor. The cDNAs of human and murine isoQCs were isolated and h-isoQC, lacking the N-terminal signal anchor and the short cytosolic tail, was expressed as a fusion protein in Escherichia coli. h-isoQC exhibits 10fold lower activity compared to hQC. Similar to hQC, h-isoQC was competitively inhibited by imidazoles and cysteamines. Inactivation by metal chelators suggests a conserved metal-dependent catalytic mechanism of both isoenzymes. A comparison of the expression pattern of m-isoQC and murine QC revealed ubiquitous expression of both enzymes. However, murine QC transcript formation was higher in neuronal tissue, whereas the amount of m-isoQC transcripts did not vary significantly between different organs. h-isoQC was exclusively localized within the Golgi complex, obviously retained by the N-terminus. Similar resident enzymes of the Golgi complex are the glycosyltransferases. Golgi apparatus retention implies a “housekeeping” protein maturation machinery conducting glycosylation and pyroglutamyl formation. For these enzymes, apparently similar strategies evolved to retain the proteins in the Golgi complex.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Biology - Volume 379, Issue 5, 20 June 2008, Pages 966–980
نویسندگان
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