Effects of various cyclodextrins on the stability of freeze-dried lactate dehydrogenase

The effects of eight cyclodextrins (CDs) on the stability of freeze-dried lactate dehydrogenase (LDH) were investigated. Five low-molecular weight saccharides were used as a reference. In the samples without saccharides, LDH activity was decreased by freeze-drying. The LDH activities of the samples with 2-hydroxypropylated CDs (HP-CDs) such as 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) showed only a small decrease and were more effective protein stabilizers than low-molecular weight saccharides. HP-beta-CD more effectively stabilized LDH than trehalose, at a sugar concentration of less than 1.0 w/w% and furthermore, a close relationship existed between the highly stabilizing effect and the degree of substitution of polar substituents.