INFLUÊNCIA DAS CONCENTRAÇÕES DE PRECIPITANTE E TAUMATINA NO ESTADO DE AGREGAÇÃO DA PROTEÍNA A BAIXAS FORÇAS IÔNICAS

Dynamic Light Scattering (DLS) studies were carried out to determine the aggregation state of thaumatin (a remarkable sweet tasting protein) in several solution conditions, involving changes on the precipitant (sodium and potassium tartrate) concentration, on the protein’s own concentration and on the temperature. The measurements show that at lower precipitant concentration as well as at lower protein concentration, the aggregation is smaller. A higher temperature also helps in reducing the residual aggregation. Such data indicate that the search for better thaumatin crystals should be directed toward those conditions. Besides, there was no significant alteration on the aggregation state at a given temperature value, even if the same value is reached after a subsequent elevation followed by a reduction (or vice versa), characterizing the aggregation phenomenon (which is little extensive) due to temperature as a reversible process. Key words: dynamic light scattering; thaumatin; protein crystallization