Glucose isomerase: insights into protein engineering for increased thermostability

摘要: Abstract Thermostable glucose isomerases are desirable for production of 55% fructose syrups at >90°C. Current commercial enzymes operate only 60°C to produce 45% syrups. Protein engineering construct more stable has so far been relatively unsuccessful, this review focuses on elucidation the thermal inactivation pathway as a future guide. The primary and tertiary structures 11 Class 1 20 2 compared. Within each class almost identical sequence differences few. Structural between less than previously surmised. thermostabilities essentially identical, in contrast previous reports, but they vary widely. In class, proceeds via tetrameric apoenzyme, metal ion affinity dominates thermostability. enzymes, subunit dissociation is not involved, there an irreversible conformational change apoenzyme leading thermostable inactive tetramer. This may be linked reversible changes alkaline pH arising from electrostatic repulsions active site, which break buried Arg-30–Asp-299 salt bridge bring Arg-30 surface. There different might explain their varying Previous protein results reviewed light these insights.