Enzyme Coated Microcrystals

Dr B.M. Moore, University of Strathclyde, Scotland

Enzyme or, more generally, protein coated microcrystals (PCMCs) are formed by dissolving the enzyme in a concentrated solution of a crystalline material such as potassium sulphate and then co-precipitating by addition of a water miscible solvent such as propanol.

The enzyme-activated sites can be titrated with benzylsulponyl fluoride and then quantified using Electrospray Ionisation Mass Spectroscopy. PCMCs in general show much enhanced reactivity over enzyme powders and retain their activity for long periods of time. In one case a PCMC that had been stored in propanol for 18 months still retained 85% of it’s original activity (this was discovered by accident!).

PCMCs show higher activity than other enzyme preparations in almost all cases provided the enzyme is soluble in the salt solution to allow formation of a good PCMC. A comparison of a PCMC derived from Candida Antarctica lipase B was compared with industrially available preparations and found to be comparable with immobilised material and significantly better than a CLEC or lyophilised material.