Heat denaturation of pepsinogen in a water‐ethanol mixture

FEBS Letters

Makarov, A.A.¹  Esipova, N.G.¹  Bazhulina, N.P.¹  Protasevich, I.I.¹ 

[1] Engelhardt Institute of Molecular Biology, Acad. Sci. Russia, Vavilov str. 32, Moscow 117984, Russian Federation

关键词: Pepsinogen;    Heat denaturation;    Ethanol;    Scanning microcalorimetry;   

DOI  :  10.1016/0014-5793(94)01308-N

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effect of ethanol and pH on thermodynamic parameters and cooperativity of pepsinogen heat denaturation was studied by scanning microcalorimetry. Addition of 20% ethanol decreases the protein denaturation temperature by 10.7°C at pH 6.4 and 15.8°C at pH 8.0. It also decreases the denaturation heat capacity increment from 5.8 to 4.2 kcal/K·mol. The dependences of calorimetric denaturation enthalpy on denaturation temperature both in water and 20% ethanol are linear and intersect at about 95°C. In 20% ethanol the pH shift from 5.9 to 8.0 results in a decreased number of cooperative domains in pepsinogen. This process causes no changes either in the secondary structure or in the local surroundings of aromatic amino acids. It is concluded that ethanol addition does not affect the cooperativity of pepsinogen denaturation substantially until the pH change provokes redistribution of charges in the protein molecule.

【 授权许可】

Unknown