The role of hydration in enzyme activity and stability: 2. Alcohol dehydrogenase activity and stability in a continuous gas phase reactor

✍ Scribed by Fangxiao Yang; Alan J. Russell

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 717 KB
• Volume: 49
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/(sici)1097-0290(19960320)49:6<709::aid-bit13>3.0.co;2-0

✦ Synopsis

The degree of enzyme hydration is the one of the most important factors which can affect enzyme activity and stability in water-limited environments. Alcohol dehydrogenase from baker's yeast (YADH) has been used as a model enzyme to study the effects of hydration on activity, stability, and cofactor stability with gas phase substrates. In all cases, the enzyme is essentially inactive until a temperature-independent degree of surface coverage by water molecules has been reached. The critical water content corresponds to 40-50% of a single monolayer. Careful control of the degree of hydration, by adjustments to gas humidity and temperature, enables the enzyme to be stabilized for periods exceeding 1 month, whereas in water the half-life of the enzyme is 30 min. The reaction with gas phase substrates follows a pseudofirst-order mechanism with an activation energy of 7.5 i- kcal/mol, which is almost half of that in aqueous solution.