everything is permitted within the laws of thermodynamics. would you not agree?

Extracting, purifying, and expressing specialized enzymes is not a cost-effective way of doing things outside of a well-funded lab.  You'd need an assortment of buffers, affinity chromatography supplies, an electrophoresis rig, not to mention other solvents and reagents such as absolute ethanol, CaCl2, and equipment for characterization. On paper, it looks somewhat straightforward, but enzymes are tricky to work with; they don't always give you the results you'd expect.