Cristalização de insulina suina com dioxido de carbono como agente acidificante / Crystallization of porcine insulin with carbon dioxide as acidifying agent

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Crystallization is a separation and purification technique used in the production of chemical, pharmaceutical and food products. The majority of the solid products is obtained by crystallization/precipitation processes that probably are the second most important separation technology in terms of capacity, behind only distillation processes. Studies on the use of volatile electrolytes such as CO2 in protein precipitation showed that these agents are a promising alternative to conventional acids. Volatile electrolytes dissolve and dissociate in water resulting in ions whose concentrations are dependent on the temperature and pressure of the system, what facilitates their removal from system. However, there is no report of the use of volatile electrolyte in protein crystallization. Therefore, the objective of this work was to study the feasibility of protein crystallization (porcine insulin) using volatile electrolyte (CO2) as crystallization agent (acidifying agent). The crystallization conditions and methodologies were adjusted in preliminary experiments. Rhombohedral crystals − the common shape for porcine insulin crystals that contain zinc in their structure − were obtained in the first crystallization runs after adjustment of pH, initial concentrations of insulin and zinc. The solubility curve for insulin in the NaHCO3/CO2/ZnCl2 system at 15°C was determined as a function of pH in the range of 6.0 to 8.0. DSC analysis of samples from dissolution and crystallization runs indicated that insulin presents different structures. Also, insulin dissolution and crystal growth kinetics as well as nucleation rate as function of supersaturation were determined with data from these experiments.

ASSUNTO(S)

dioxido de carbono carbon dioxide crystallization proteins cristalização proteinas insulina insulin

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