CHED 964 |
| N-terminal pyroglutamate formation from glutaminyl-containing precursors is an essential posttranslational process for many bioactive peptides. Although this reaction may proceed spontaneously, the efficiency is greatly enhanced by the enzyme glutaminyl cyclase (QC). This study examines substrate preference in order to characterize a proposed yeast glutaminyl cyclase enzyme (yQC). This process was initiated by cloning the gene for yQC into a plasmid for storage and over expression. The resulting recombinant plasmid was expressed in an E.coli system and purified via a cobalt affinity column. The enzyme activity was determined using a coupled assay with á-ketogluterate and NADH in a five component system. The current characterization experiments determine kinetic constants, such as Km, Vmax and Kcat, for various glutaminyl containing substrates then compare them with previously published kinetic constants for the human enzyme. Although the function remains unclear, the results presented here suggest that yQC catalyzes the same reaction as hQC enzyme. |
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Undergraduate Research Poster Session: Biochemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |