Savinase is a serine protease, that you probably all seen in action. This is due to its wide use as an enzyme in detergents. Proteases are amazing enzymes breaking down other proteins into smaller and smaller chunks. Savinase does this by hydrolysing the peptide bonds that bind the aminoacids of proteins together. It does this by using a catalytic triade, where three aminoacids form a charge relay to make a powerful nucleophilic attack on peptide bonds. In savinase, aspartate32 is hydrogenbonded to histidine64 thereby increasing the pKa of the imidazole-ring considerably. This in turn makes histidine a strong enough base to deprotonate serine221, which then attacks and breaks the peptide bond of a bound substrate. Even though the asp, his and ser residues are quite far apart in the backbone of savinase, the specific 3D folding of the protein brings them close enough together to enable their catalytic function. Substrates are bound in the ridge that is easily found in the printed structure. In this surface render, only the histidine and serine residues are visible (as seen on the pictures), the aspartate lies deeper in the enzyme just behind the histidine (indicated by the purple dots). NB. the model does not contain any color information - I crave a multi-color upgrade of my reprappro badly!Layer height .1 for most beautiful result and test of patience ;) .2 for sadisfactory result Infill .2 to .4 or whatever suits your printer. Since this is a bulky molecule, use an appropriate amount of infill to not waste too much of your filament. Supports Due to the complex structure of proteins, supports are required and a bit of work removing them from the holes and caverns of the protein is a bit time consuming. Please see this process as an exploration of this amazing structure.