To rationalize the increase in activity of the three active variants, models were generated in silico and compared to that of the E. coli wild type DERA. The binding pockets volumes for all four enzymes were analyzed using fpocket and compared. As predicted, mutation of the selected residues to alanine resulted in an increase in the volume of the active site for all variants. The WT enzyme has a binding pocket volume of 317 Å 3 , this increases to 416 Å 3 for L20A, 447 Å 3 for F76A and 529 Å 3 for L20A/F76A. These increases in binding pocket size seem to correlate with the trend of activity observed, with only smaller donor molecules like glycolaldehyde and propanal being active with the WT, whereas the variants with significantly increased binding pocket volumes are able to accommodate larger substrates. Particularly bulky substrates such as benzoxylacetaldehyde or methoxy(ethoxy)acetaldehyde also show better activity with the larger binding pockets of F76A and L20A/F76A.