title: Interaction of alphaS1-casein with curcumin and its biological implications.
abstract: alpha(S1)-Casein is one of the major protein components of the casein fraction of milk. Curcumin (diferuloyl methane), the major curcuminoid, constituting about 2-5% of turmeric (Curcuma longa ) is the active ingredient with many physiological, biochemical, and pharmacological properties. On the basis of spectroscopic measurements, it is inferred that curcumin binds to alpha(S1)-casein at pH 7.4 and 27 degrees C with two binding sites, one with high affinity [(2.01 +/- 0.6) x 10(6) M(-1)] and the other with low affinity [(6.3 +/- 0.4) x 10(4) M(-1)]. Binding of curcumin to alpha(S1)-casein is predominantly hydrophobic in nature. The anisotropy of curcumin or conformation of alpha(S1)-casein did not change on interaction. The stability of curcumin in solution at pH 7.2 was enhanced on binding with alpha(S1)-casein. The chaperone-like activity of alpha(S1)-casein gets slightly enhanced on its binding to curcumin. The ability of curcumin to protect erythrocytes against hemolysis was not affected due to curcumin- alpha(S1)-casein interaction. The two binding sites of alpha(S1)-casein for curcumin, along with enhanced solution stability on interaction, may offer an alternative approach in physiological and nutritional applications.
authors.affiliation: Department of Protein Chemistry and Technology, Central Food Technological Research Institute (A Constituent Laboratory of the Council of Scientific and Industrial Research), Mysore 570020, India.
authors.forename: Athahalli H
authors.initials: AH
authors.lastname: Sneharani
authors.forename: Sridevi Annapurna
authors.initials: SA
authors.lastname: Singh
authors.forename: A G
authors.initials: AG
authors.lastname: Appu Rao
mesh_terms: D000818:Animals; D001665:Binding Sites; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D003474:Curcumin / Q000737:chemistry* / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D007700:Kinetics; D008968:Molecular Conformation; D011485:Protein Binding
chemical_list: D002364:Caseins; D003474:Curcumin