Study of proteases in pursuit of application for catalysis in non-conventional media

MORCELLE DEL VALLE, S. R.; PRIOLO, N. S.; BARBERIS, S.; CAFFINI, N. O.

Villa Carlos Paz, Córdoba, Argentina

Congreso; XXXVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2001

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

STUDY OF PROTEASES IN PURSUIT OF APPLICATION FOR CATALYSIS IN NON-CONVENTIONAL MEDIA   Morcelle del Valle, Susana1*; Priolo, N.1; Barberis, S.2 and Caffini, N.1**   1LIPROVE, Fac. de Cs. Exactas, UNLP, calles 47 y 115 (1900), La Plata. E-mail: morcelle@biol.unlp.edu.ar. *CONICET. **CIC. 2Cátedra de Bromatología. Fac. de Química, Bioquímica y Farmacia, UNSL. Chacabuco y Pedernera (5700). San Luis, Argentina.   OBJECTIVES. This communication deals with the determination of suitability of proteases present in the latex of Funastrum clausum (Jacq.) Schlechter (Asclepiadaceae) for peptide synthesis in monophasic and biphasic media instead of conventional chemical synthesis. EXPERIMENTAL. Latex obtained of stems was gathered on 55 mM citric-phosphate buffer (pH 6.4) with EDTA and cysteine. Crude extract was obtained by ultracentrifugation at 100,000´g for 1h. Stability in different biphasic and monophasic aqueous (Tris-HCl buffer 0.1M, pH 8.8)-organic media was proved by incubation of crude extract in 70:30, 50:50 and 30:70 mixtures for three hours and then caseinolytic residual activity was measured. Aminoacidic preferencies were determined by endosterolytic assays, which were performed with N-alfa-carbobenzoxy-p-nitrophenyl esters of amino acids. RESULTS AND CONCLUSSIONS. Stability assays in different organic-aqueous system proved that when methanol and ethanol are used as co-solvents, residual proteolytic activity seemed to increase, whereas in biphasic systems the activity was reduced, showing the poor stability of peptidases present in crude extract in this kind of media. The highest endoesterolytic activity was obtained with the Ala derivative, followed by those of Asn and Tyr.