Glass transition of myoglobin crystal

✍ Scribed by Y. Miyazaki; T. Matsuo; H. Suga

• Book ID: 103030144
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 438 KB
• Volume: 213
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)85136-c

✦ Synopsis

Heat capacities of monoclinic horse myoglobin crystals containing different amounts of water have heen measured in the temperature range between 8 and 300 K. The samples containing 48.9 and 19.0 mass% of water underwent glass transitions at Tg= 188 and 216 K, respectively. The heat capacity increased from the rigid lattice value for T< T, to the supercooled liquid value for T> TI with concomitant spontaneous exothermic and endothermic enthalpy relaxation. The glass transition at 188 K shifted to 172 K when the sample was annealed at 230 K. The temperature drift rate due to the relaxation was analyzed to derive relaxation times as a function of the temperature and water content. The Arrhenius parameters of the relaxation time are discussed in relation to the molecular mechanism of the glass transition.