The presence of an N-terminal pyroglutamic acid residue is critical to the biological activity of numerous neuropeptides and peptide hormones. The objective of this project is to elucidate the enzymatic mechanism by which pyroglutamic acid residues are formed on peptides. To accomplish this, sensitive couple assays for the enzyme responsible, glutamine cyclotransferase, will first be developed along with a rapid purification procedure for this enzyme from bovine pituitary. The subsite specificity of this enzyme will then be determined using a series of product inhibitors. The chemical mechanism of this enzyme will also be studied and inhibitors. The chemical mechanism of this enzyme will also be studied and inhibitors developed against it to be used in a cell culture system to study the biosynthesis of the thyrotropin releasing hormone (TRH). Finally, both monoclonal and polyclonal antibodies will be raised against QC which will be used to determine the tissue distribution and immunohistochemical localization of this enzyme.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29DK041892-05
Application #
2141974
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1990-06-01
Project End
1996-05-31
Budget Start
1994-06-15
Budget End
1996-05-31
Support Year
5
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Southern Mississippi
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
City
Hattiesburg
State
MS
Country
United States
Zip Code
39406
Gololobov MYu; Song, I; Wang, W et al. (1994) Steady-state kinetics of glutamine cyclotransferase. Arch Biochem Biophys 309:300-7
Gololobov MYu; Bateman Jr, R C (1994) gamma-Glutamyltranspeptidase-catalysed acyl-transfer to the added acceptor does not proceed via the ping-pong mechanism. Biochem J 304 ( Pt 3):869-76
Song, I; Chuang, C Z; Bateman Jr, R C (1994) Molecular cloning, sequence analysis and expression of human pituitary glutaminyl cyclase. J Mol Endocrinol 13:77-86