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ARS Home » Midwest Area » Madison, Wisconsin » Cereal Crops Research » Research » Publications at this Location » Publication #121156
Title: THE EFFECT OF PROLINE INSERTIONS ON THE THERMOSTABILITY OF A BARLEY ALPHA-GLUCOSIDASE

Author
item MUSLIN, ELIZABETH - UNIV WISCONSIN-MADISON
item CLARK, SUZANNE - UNIV WISCONSIN-MADISON
item Henson, Cynthia

Submitted to: Brewers Digest
Publication Type: Abstract Only
Publication Acceptance Date: 6/25/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The thermal stability of alpha-glucosidase is important because the conversion of barley starch to fermentable sugars during industrial production of ethanol (e.g. brewing, fuel ethanol production) typically takes place at temperatures of 65-73 degrees Celsius. We investigated the thermostability of alpha-glucosidases from four plant species, compared their deduced amino acid sequences, and tested the contribution of proline residues to the thermostability of alpha-glucosidase. The alpha- glucosidase from barley (Hordeum vulgare) was significantly less thermostable than the other three alpha-glucosidases. A comparison of the published deduced amino acid sequences of these four alpha-glucosidases revealed conserved proline residues in the three most thermostable alpha- glucosidases that were not found in the barley enzyme. Site-directed mutagenesis was done on recombinant barley alpha-glucosidase to create proteins with prolines at these conserved positions. The thermostability (T50) of one of these mutant enzymes was 10 degrees Celsius higher than the non-mutated enzyme.