Physical nature of the phase transition in globular proteins

FEBS Letters

Pfeil, Wolfgang¹  Bychkova, Valentina E.¹  Ptitsyn, Oleg B.² 

[1] Central Institute of Molecular Biology. Academy of Sciences of the GDR, 1115 Berlin, GDR;Institute of Protein Research, Academy of Sciences of the USSR, 142292 Poustchino, Moscow Region, USSR

关键词: Protein unfolding;    Molten globule state;    α-Lactalbumin;    Scanning calorimetry;    Isothermal calorimetric titration;    (Human);    Hα-LA;    human α-lactalbumin;    BαLA;    bovine α-lactalbumin;    GuHCl;    guanidine hydrochloride;    Mops;    4-morpholinepropanesulfonic acid;    CD;    circular dichroism;   

DOI  :  10.1016/0014-5793(86)80422-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The guanidine hydrochloride-induced unfolding of human α-lactalbumin has been studied by isothermal calorimetry. It has been shown that a cooperative transition takes place only in the concentration interval of the denaturant between 0.3 and 2 mol · 1⁻¹. The cooperative transition coincides with the transition detected by circular dichroism in the near-ultraviolet region which reflects the destruction of the specific environment of aromatic side groups. According to scanning calorimetric investigations, the transition disappears in the acid form of the protein where circular dichroism of aromatic side groups is practically absent. At higher concentrations of guanidine hydrochloride, where destruction of the secondary structure and un- folding of the chain are observed, there is no cooperative heat absorption.

【 授权许可】

Unknown