Activation volume of crystallization and effects of pressure on the three-dimensional nucleation rate of glucose isomerase

Abstract

The activation volume, Δ V ^‡, of the solute incorporation process at the kink site of a glucose isomerase (GI) crystal was estimated using the pressure dependency of the step kinetic coefficient, β_step, and the three-dimensional nucleation rates J of GI crystals were analyzed using classical nucleation theory. Δ V ^‡ took a negative value. The sticking parameter, s, for the addition of a GI tetramer to a critical nucleus drastically increased with increasing pressure. This was probably due to the decrease in the activation energy needed for the addition of the GI tetramer.

Keywords:

• activation volume
• nucleation rate
• glucose isomerase
• solubility
• step kinetic coefficient

Acknowledgements

This work was partially supported by Grants-in-Aid (Nos. 16760014 and 19760009 (Y.S.)) for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.