Functional characterization and specific effects of various peptides on enzymatic activity of a DPP-III homologue from goat brain

Abstract

The purified dipeptidyl aminopeptidase from goat brain showed several characteristics similar to DPP-III although it possesses a dissimilar molecular weight and different inhibition behavior. The enzyme was found to be inhibited by metallochelators and thiol inhibitors which could be reversed by introducing metals and thiols, respectively. The enzyme activity is also significantly affected by DMSO and ethanol. It was found to be highly sensitive to even very low concentration of urea. The inhibitory potency of several dipeptides and bioactive peptides on this enzyme was investigated to characterize its active site. The highest potency was observed for the dipeptides having aromatic and bulky side chains such as Phe-Met, Leu-Arg, Met-Arg, Trp-Met and Leu-Trp.

Keywords::

• Dipeptidyl aminopeptidase
• metallo enzyme
• goat brain
• Arg-Arg-4-methoxy-β-naphthylamide
• DPP
• thiol enzyme
• inhibition

Acknowledgements

Suman Dhanda is thankful to University authorities of Kurukshetra University, Kurukshetra and University Grants Commission (UGC), New Delhi for providing the financial help in the form of a University Research Scholarship and JRF, respectively, to carry out the work.