Thermal stability of human haemoglobin in the presence of sarcosine and sorbitol

Sarcosine and sorbitol at 10-30% (w/w) stabilized haemoglobin from human er ythrocytes to thermal denaturation. At 65 degrees C, the protein's half lif e was increased from 0.85 to 50 min in 30% sarcosine and to 24 min in 30% s orbitol. A kinetic analysis based on the Lumry-Eyring mechanism of inactiva tion showed that the denaturation process can be described by a second-orde r rate expression with an apparent activation energy ranging from 56 to 87 kcal mol(-1).