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Isolation of Glutaminyl Cyclase from Saccharomyces cerevisiae
Author(s) -
Boswell Mikki,
Terrell David,
Booth Rachell E
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1022-d
Subject(s) - saccharomyces cerevisiae , isolation (microbiology) , chemistry , microbiology and biotechnology , biochemistry , biology , yeast
Glutaminyl cyclase (QC) (2.5.2.3) catalyzes the cyclization of the N‐terminal glutamine residues of peptides and proteins. Although the in vivo role of QC is not well understood, recent interest in QC has been generated by studies that have linked QC activity in human neuroendocrine tissues to diseases such as Alzheimer’s and osteoporosis. Despite the fact that QC has been isolated and characterized in multiple mammalian species, no attempt has been made to isolate the QC form present in the yeast Saccharomyces cerevisiae . Elucidation of QC function in genetically tractable yeast cells may serve as a model for examining the function in higher eukaryotes. Therefore, this study sought to isolate and begin the characterization of yeast QC. A purification scheme was constructed and spectrophotometric and fluorometric activity assays were used to confirm QC activity in partially purified extracts. QC fractions were found to have a maximum activity of ~5.1 nmol/min using the spectrophotometric assay. Initial inhibition studies with imidazole, a well characterized inhibitor of mammalian QC forms, resulted in decreased activity for QC fractions. Additional steps for the complete purification of yeast QC, which would allow for further kinetic characterization and sequence analysis, are currently being pursued. Funding for this project has been provided by the Department of Chemistry and Biochemistry at Texas State University – San Marcos.