Equilibrium denaturation of buffalo pituitary growth hormone.

To understand the structural properties of buffalo growth hormone (buGH), the equilibrium denaturation using guanidinium chloride (GdmCl) was carried out and was monitored by ultraviolet absorption spectroscopy, intrinsic fluorescence spectroscopy, far UV-circular dichroism and size-exclusion chromatography. The normalized denaturation transition curves for each of the above methods were not coincident, showing that buGH does not follow a simple two state folding mechanism. Further, size-exclusion chromatography also showed the presence of an associated intermediate during the unfolding of buGH. It was observed that in buGH, denaturation resulted in an initial disruption of the tertiary structure, whereas the secondary structure and the degree of compactness were disrupted at a higher concentration of the denaturant. This suggests that buGH follows the hierarchical model of protein folding.

Otimizaçäo da extraçäo de hormônio de crescimento humano a partir de hipófises congeladas / Improvements of the extraction of human growth hormone from frozen hypophysis

Descreve-se a otimizaçäo de um método de extraçäo de hormônio de crescimento humano (hGH) a partir de hipófises humanas congeladas. As alteraçöes introduzidas na metodologia permitiram aumentar o rendimento para 8,7 mg de hGH por glândula processada. O hormônio obtido possui 21.587 daltons de peso molecular e a forma íntegra (hGH-22k) constitui 68% da preparaçäo. O hormônio isolado mostrou-se ativo em radioimunoensaio