Book of Abstracts: Albany 2011

category image Albany 2011
Conversation 17
June 14-18 2011
©Adenine Press (2010)

Improving in Digestion and Antioxidant Activity of β-lactoglobulin using Newly designed Copper Complexes as Artificial Proteases

Beta-lactoglobulin (BLG) is a major protein of whey and has wide application as a food ingredient (1-2). Stable structure of bovine whey proteins, especially BLG, restricts their hydrolysis by proteases and it leads to allergy reactions (3). Now-a-days, the design of synthetic metallo-proteases that cleave proteins at a specific site has elicited much interest (4). Hence, in the present investigation, we have decided to design and synthesize a new class of cooper(II) complexes ({Cu(bpy)Cl2 }, {Cu(bpy) 2 }Cl2, {Cu(dien)OH2 }(NO3) 2 and {Cu(trien)}(NO3) 2) as artificial protease in order to hydrolyze resistant BLG. We also examine the antioxidant activity of fragmented BLG using SDS-PAGE and different spectrophotometric methods (Fluorescence and UV-Visible). Incidentally copper complexes are very important in biological systems; they have been used to locate nucleosome positioning (5), they occur widely in oxidative proteins such as laccases (6), and participate in many many cellular processes and are implicated in pathogenesis of many diseases (7).

SDS -PAGE of BLG incubated with different Cu(II) complexes for 30 h represented fragmentation of the protein. Also, increasing fluorescamine intensity measurements prove hydrolysis or fragmentation of protein in the presence of different Cu(II) complexes. SDS-PAGE and fluorescamin studies show that complex 3 has higher protease activity against BLG. The antioxidant activities of native and hydrolyzed BLG were determined by an ABTS°+ radical cation assay. The degree of decolorization of ABTS radical induced by native and hydrolyzed BLG resulting from different Cu(II) complexes were compared to that induced by Trolox. Results have represented that hydrolyzed BLG using complexes 2 and 3 exhibit significantly greater antioxidant activity than the other hydrolyzed or native BLG, probably signifying the greater number of solvent-exposed amino acids available for scavenging of the free radicals.

From above results, it can be concluded that our new designed Cu(II) complexes have artificial protease activities against model protein of BLG. Also, hydrolysing of BLG can enhance its fragmentation by proteases and increase its antioxidant activity.


  1. S.C. Cheison, M. Schmitt, L. Elena, T. Letzel., U. Kulozik, Food Chemistry. 121, 457–467 (2010).
  2. L. Tavel, C. Moreau, S. Bouhalla, E. Li-Chan, Food Chemistry. 119, 1550–1556 (2010).
  3. M. Besler, P. Eigenmann, R.H. Schwartz, Food Allergens. 4, 199-106 (2002).
  4. M. S. Kim, J. Suh, Bull. Korean Chem. Soc. 26, 1911-1919 (2005).
  5. A. Travers, E. Hiriart, M. Churcher, M. Caserta, E. Di Mauro, J Biomol Struct Dyn 27, 713-724 (2010).
  6. M. T. Cambria, D. Di Marino, M. Falconi, S. Garavaglia, A. Cambria, J Biomol Struct Dyn 27, 501-509 (2010).
  7. H. F. Ji, H. Y. Zhang, J Biomol Struct Dyn 26, 197-201 (2008).

Adeleh Divsalar1*
Sajedeh Ebrahim-Damavandi2
Ali Akbar Saboury2
Hassan Mansouri-Torshizi3

1Department of Biological Sciences
Tarbiat Moallem University
Tehran, Iran
2 Institute of Biochemistry and Biophysics
University of Tehran. Tehran, Iran.
3 Department of Chemistry
University of Sistan and Baluchestan
Zahedan, Iran

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