Enzyme purification with aqueous two-phase systems: comparison between systems composed of pure polymers and systems composed of crude polymers

摘要

The main drawback when using aqueous two-phase systems for macromolecule purification is the high cost of mostpolymers used. The purification of an enzyme, alcohol dehydrogenase, from a crude extract of Saccharomyces cerevisiaewas tested in systems composed of poly(ethylene glycol) and a crude hydroxypropyl starch or Reppal PES 100, a purifiedfraction of hydroxypropyl starch. Purification factors measured for the enzyme were very similar in both systems (between0.8 and 1.4 for both systems in the upper phase). However, systems composed of Reppal PES present a greater recovery ofenzyme, between 77% and 100% versus 60% and 100%, while systems composed of crude hydroxypropyl starch exhibit alarger Δlog K for the tested ligand, 1.26 versus 0.81.