Fluorescence and absorption spectroscopic studies on the interaction of porphyrins with snake gourd (Trichosanthes anguina) seed lectin

Komath, Sneha Sudha ; Kenoth, Roopa ; Giribabu, Lingamallu ; Maiya, Bhaskar G. ; Swamy, Musti J. (2000) Fluorescence and absorption spectroscopic studies on the interaction of porphyrins with snake gourd (Trichosanthes anguina) seed lectin Journal of Photochemistry and Photobiology B: Biology, 55 (1). pp. 49-55. ISSN 1011-1344

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S10111...

Related URL: http://dx.doi.org/10.1016/S1011-1344(00)00026-9

Abstract

The interaction of several free-base porphyrins and their corresponding copper(II) and zinc(II) derivatives with the galactose-specific lectin from snake gourd (Trichosanthes anguina) seeds has been investigated by absorption and fluorescence spectroscopic techniques. The lectin dimer contains two apparently equivalent binding sites for the porphyrins. Association constants obtained for the interaction of various porphyrins with the lectin are in the range 1.7×104-6.2×105 M-1, with the metalloporphyrins being seen to have higher affinity for the lectin compared with the free-base analogues. Both positively charged and negatively charged porphyrins bind to snake gourd seed lectin (SGSL) with comparable affinities, suggesting that binding occurs primarily via hydrophobic interactions. Further, binding of porphyrins is found to be largely unaffected by the presence of the sugar ligand, lactose, indicating that the binding sites for the carbohydrate and porphyrin are different. This study thus suggests that the lectin may serve as a receptor for some endogenous non-carbohydrate, hydrophobic ligand in vivo, in addition to the saccharide ligands. It also opens up the possibility of employing the T. anguina lectin in applications such as photodynamic therapy, which involve the use of porphyrins.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Porphyrin; Photodynamic Therapy; Snake Gourd Seed Lectin; Trichosanthes Anguina Agglutinin; Haemagglutinin; Fluorescence Spectroscopy; Absorption Spectroscopy
ID Code:31955
Deposited On:31 Mar 2011 10:00
Last Modified:09 Jun 2011 09:37

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