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Updated: Jul 9, 2026

Glutamine Flux Imaging Using Genetically Encoded Sensors
Published on: July 31, 2014
Substrate and inhibitor specificity of glutamine cyclotransferase (QC)
M Y Gololobov1, W Wang, R C Bateman
1Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg 39406-5043, USA.
Abstract:
This paper reports a systematic study of the substrate and inhibitor specificity of papaya latex glutamine cyclotransferase (QC). The results showed that the second amino acid residue in N-terminal glutaminyl peptides significantly accelerated papaya latex QC-catalyzed reactions while the third residue provided no further rate enhancement. Substrate binding was shown to be the main specificity-determining step. Fifteen proline derivatives and dipeptides containing an N-terminal proline were tested and found to inhibit papaya latex QC. This supports our previous molecular modeling study of the QC catalytic pathway which suggested a structure of the reaction intermediates similar to that of L-proline.
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