Abstract
During freeze-drying and rehydration, the activity of the H+-ATPase from the plasma membrane of Kluyveromyces lactis was preserved by increasing concentrations of carbohydrates. When the H+-ATPase was freeze-dried in the absence of carbohydrates the activity was lost. The protective efficiency of carbohydrates was as follows: trehalose > maltose > sucrose > glucose > galactose. Each carbohydrate exhibited the maximal protection at a concentration of 20 mg carbohydrate per milligram of protein or above. No structural changes of the rehydrated H+-ATPase were detected by intrinsic fluorescence measurements. Trehalose, at 20 mg/mg protein, protected the enzyme activity completely during freeze-drying and rehydration. Rehydration temperature was critical; at 20°C or below, activity was fully retained, while at 30, 40, or 50°C activity decreased in proportion with temperature. The trehalose-protected freeze-dried H+-ATPase was stored at different temperatures for up to 60 days. Storage at 4°C resulted in retention of most of the enzymatic activity, while storage at 20 or 30°C resulted in loss of activity. The protection of the H+-ATPase by trehalose suggests that this carbohydrate might protect other membrane enzymes from inactivation during handling.
Original language | English |
---|---|
Pages (from-to) | 131-138 |
Number of pages | 8 |
Journal | Cryobiology |
Volume | 37 |
Issue number | 2 |
DOIs | |
State | Published - Sep 1998 |
Externally published | Yes |
Keywords
- Carbohydrates
- Freeze-drying
- H-atpase
- Protein stabilization
- Trehalose