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Enzyme Research
Volume 2011 (2011), Article ID 897028, 3 pages
Research Article

Activity Staining and Inhibition Characterization of Dipeptidylpeptidase-III Enzyme from Goat Brain

Department of Biochemistry, Kurukshetra University, Haryana, Kurukshetra 136119, India

Received 12 January 2011; Accepted 21 February 2011

Academic Editor: William David Nes

Copyright © 2011 Pooja Attri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Dipeptidylpeptidase-III (DPP-III) from goat brain was purified and characterized using Arginyl-Arginyl-4-methoxy-β-naphthylamide (Arg-Arg-4mβNA) substrate. This enzyme retained its activity in native 10% polyacrylamide gel when stained using Arg-Arg-4mβNA. The activity was significantly increased by 100 mM chloride. Studies for its inhibition with some peptides and chemical inhibitors revealed that Leu-Trp-Met-Arg-Phe-Ala was most potent inhibitor followed by Arg-Phe-Ala and Gly-Phe-Leu. All the studied chemical inhibitors caused 40–50% inhibition at 1 mM. Metal ions helped to regain activity of EDTA pretreated enzyme. ZnCl2 at 50 μM almost completely restored the enzyme activity. Further ZnCl2 and CoCl2 exerted protective effects on EDTA pretreated enzyme for its susceptibility to DTNB inhibition. Therefore, DPP-III is a metalloprotease with the involvement of cysteine residues either located at the catalytic site or involved in regulation.