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Bubbles in bread - Opportunities for psychrophilic endo-xylanases as bread improver

8 important questions on Bubbles in bread - Opportunities for psychrophilic endo-xylanases as bread improver

They are most active at temperatures between 40-60C.

They have their optimum activity at lower temperatures, preferably around the usually applied mixing temperature of dough of 20C.

A smaller amount of enzyme (on weight basis) is needed, which is cheaper.

They have a temperature optimum of 70C.

No, a smaller substrate-binding groove than thermophilic ones. The secondary structure elements are quite similar between these two enzymes.

The active site of psychrophilic enzyme displays much higher flexibility, which facilitates substrate-binding in low temperature environment, where diffusion is slower.
The increased flexibility is associated with the reduced thermostability of these enzymes.

The amino acids forming subsites +1 and +2 dramatically alter their orientation upon binding of substrate. In the active site, amino acids can move around freely in order to help capture the substrate.
Reduced number of salt bridges
Increased exposure of hydrophobic residues
This adaptability of the active site is typical for psychrophilic enzymes. It seems as if these enzymes actively catch the substrate.

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