中文摘要：

引言 甜菜碱作为一种渗透剂（osmolyte）在自然界中广泛存在。许多研究表明其对蛋白质结构具有一定的稳定作用。Caldas等发现甜菜碱可以抑制体内柠檬酸合成酶的热聚集，并可以促进其体外复性。Bourot等在对二氨基庚二酸盐脱羧酶（DAPDC）折叠过程的研究中也发现，无论在体内还是体外甜菜碱均有促进复性的作用，并认为其与分子伴侣的作用机制不尽相同。

英文摘要：

Equilibrium denaturation of lysozyme by guanidinium chloride in the presence of betaine was investigated by tryptophan fluorescence. Betaine was used as a folding aid to enhance the renaturation of denatured-reduced lysozyme, the refolding kinetic behavior was studied at a low guanidinium chloride concentration by a competitive model of first-order folding reaction and third-order aggregation. It was found that betaine could shift in the transition midpoint in the guanidinium chloride induced equilibrium unfolding experiments, indicating that betaine could improve the thermodynamic stability of lysozyme. In the presence of betaine, the aggregation rate was decreased and the refolding rate was increased, the refolding yield could be increased.