A Spectrophotometric Assay For Glutaminyl-Peptide Cyclizing Enzymes

Authors

Robert C. Bateman Jr., University of Southern MississippiFollow

Document Type

Article

Publication Date

1-1-1989

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Abstract

Current assays for the glutaminyl-peptide cyclizing enzyme, glutaminyl cyclase, have several shortcomings. In this report a rapid spectrophotometric assay for cyclization of glutaminyl-peptides to pyroglutamyl-peptides by glutaminyl cyclase is described which overcomes many of these shortcomings. This coupled assay utilizes glutamate dehydrogenase, α-ketoglutarate and NADH to measure the ammonia released during cyclization of the dipeptide substrate Gln-Gln. Glutaminyl cyclase from bovine pituitary, partially purified by ion exchange chromatography, exhibits a K_m for this substrate of 0.6 mM and a V_max of 9.6 nmol/min/mg protein. These values are comparable to ones previously reported using other glutaminyl-peptide substrates and either radioimmunoassay or high-performance liquid chromatography to measure glutaminyl cyclase activity.

Publication Title

Journal of Neuroscience Methods

Volume

30

Issue

1

First Page

23

Last Page

28

Recommended Citation

Bateman, R. C. (1989). A Spectrophotometric Assay For Glutaminyl-Peptide Cyclizing Enzymes. Journal of Neuroscience Methods, 30(1), 23-28.
Available at: https://aquila.usm.edu/fac_pubs/19622