Heat denaturation of pepsinogen in a water-ethanol mixture.


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 degrees C at pH 6.4 and 15.8 degrees 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 degrees 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. Study holds ProTherm entries: 9828, 9829, 9830, 9831, 9832, 9833, 9834, 9835, 9836, 9837, 9838, 9839, 9840 Extra Details: pepsinogen; heat denaturation; ethanol; scanning microcalorimetry

Submission Details

ID: eiChr5fS3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:38 p.m.

Version: 1

Publication Details
Makarov AA;Protasevich II;Bazhulina NP;Esipova NG,FEBS Lett. (1995) Heat denaturation of pepsinogen in a water-ethanol mixture. PMID:8001679
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