ENZYME-PURIFICATION WITH AQUEOUS 2-PHASE SYSTEMS - COMPARISON BETWEENSYSTEMS COMPOSED OF PURE POLYMERS AND SYSTEMS COMPOSED OF CRUDE POLYMERS

The main drawback when using aqueous two-phase systems for macromolecu le purification is the high cost of most polymers used. The purificati on of an enzyme, alcohol dehydrogenase, from a crude extract of Saccha romyces cerevisiae was tested in systems composed of poly(ethylene gly col) and a crude hydroxypropyl starch or Reppal PES 100, a purified fr action of hydroxypropyl starch. Purification factors measured for the enzyme were very similar in both systems (between 0.8 and 1.4 for both systems in the upper phase). However, systems composed of Reppal PES present a greater recovery of enzyme, between 77% and 100% versus 60% and 100%, while systems composed of crude hydroxypropyl starch exhibit a larger Delta log K for the tested ligand, 1.26 versus 0.81.