Volatile anesthetics alter protein stability

1. We have used differential scanning calorimetry to measure the halothane induced change in stability of five lipid-free proteins in aqueous solution. 2. The temperature at peak heat capacity (T-m) as the sample is heated provides a measure of stability. 3. Addition of halothane increases T-m for bovine and human serum albumin, but decreases T-m for hen egg white lysozyme, bovine pancreatic ribonuclease A, and horse skeletal muscle myoglobin. 4. A shift of T-m in either direction may model the action of inhaled anesthetics on relevant proteins in the central nervous system. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.