A spectroscopic study of the pH-effect on the interaction between norharmane alkaloid and Bovine Serum Albumin.

FEDERICO A. RASSE SURIANI; M. MICAELA GONZALEZ; ROSA ERRA-BALSELLS; FRANCO M. CABRERIZO

Ciudad Autonoma de Buenos Aires

Conferencia; 3rd South American Workshop & International Gregorio Weber Conference; 2011

Lab. de Bioquímica Estructural. Fac. de Ciencias Exactas y Naturales. Universidad de Buenos Aires.

β-carboline (βCs) alkaloids belong to a family of heterocyclic compounds that shows in its structure the 9H-pyrido[3,4-b]indole moiety or norharmane (Scheme 1). These alkaloids are found in a great variety of living systems such as plants, cells, mammals, etc. In mammalian body, βCs occur as normal constituents in plasma, platelets and urine. However, under certain conditions such as after alcohol intake and smoking βCs basal levels (~ 0.1 nmol/l) are considerably increased (~ 1 nmol/l).             Regarding their biological functions, a variety of significant photo-dependent roles have been described, e. g., in plants βCs could be involved in the defense response (via photo-toxic effects). In addition, these alkaloids are able to act as good photosensitizers: e. g., upon UV-A excitation, some βCs are able to induce DNA relaxation1 or chromosome damage in mammalian cells2, and also to inactivate bacteria3 and viruses4.             Certainly, the study of the binding interaction between βCs with different biomolecules becomes significant for studying the net photodynamic efficiency. Thus, in the present work, we have investigated the pH-effect on the interaction between norharmane and Bovine Serum Albumin (BSA), a well know model protein transport. Results would help to understand the photophysical behavior of these alkaloids in biological environments and to better assess the correlation between alkaloids prototropic forms and the biological activity.