Stability of araujiain, a novel plant protease, on different organic systems.

EVELINA QUIROGA; NORA PRIOLO; JOSÉ MARCHESE; SONIA BARBERIS

ACTA FARM. BONAERENSE

Colegio de Farmaceúticos de la Provincia de Buenos Aires

Lugar: Buenos Aires; Año: 2005 vol. 24 p. 204 - 208

0326-2383

The effect of different organic solvents on the stability (residual caseinolytic activity) of araujiain in mixtures of buffer and different water-miscible or immiscible organic solvents, and in continuous systems (organic solvents with low water activity) after 4h at 40ºC was studied in this paper in order to select the most adequate media for peptide enzymatic synthesis. Araujiain showed the highest stability in 50 % hexane, 50 % propanone, and N,N-dimethylformamide (aw: 0.5 in the enzyme), and those values were remarkably greater than in buffer. In addition, the presence of those organic solvents reduced the autolysis degree. In general, araujiain in aqueous-miscible organic systems was not inactivated and the enzyme showed higher activities in those media than in buffer. In biphasic systems, the partition of the organic solvents into the aqueous phase activated the enzyme in several cases. These results did not agree with those obtained in continuous systems, because many of them inactivated the enzyme. Nevertheless, in N,N-dimethylformamide (aw: 0.5 in the enzyme) araujiain showed a remarkable stability after 4h, and it displayed a higher activity in this organic solvent than in aqueous medium. From these results, it is evident that araujiain in the presence of most of the studied organic systems did not suffer unfolding and it was able to retain its native or native-like configuration, though with altered characteristics or properties. This fact was demonstrated by means of comparative FTIR spectroscopy studies for araujiain in buffer and non-aqueous systems.