Studies of protein partition in non conventional aqueous two-phase

PELLEGRINI, L; B. NERLI; G, PICÓ

SEPARATION AND PURIFICATION TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2011 vol. 78 p. 91 - 96

1383-5866

Aqueous two phase systems (ATPSs) formed by polyethyleneglycol (PEG) and sodium tartrate (NaTart)  pH 5.00 are non conventional systems of low impact. Their ability to purify trypsinogen (TRPz) and alphachymotrypsinogen  (ChTRPz) from bovine pancreas was evaluated. The effect of several variables such as  molecular weight of PEG, tie line length and phase–volume ratio on zymogen partitioning was explored. Those systems formed by PEG of molecular weight 600 (20.62%, w/w) and NaTart (12.85%, w/w) with a  phase–volume ratio equal to one were found to evidence the best purification performance, and were  employed to design a two-stage purification process  Firstly, a ATPS extraction step yields both to recover most of pancreatic TRPz and ChTRPz (76% and 87%  respectively) in the PEG600 enriched-top phase and to eliminate other pancreatic homogenate components  – cell debris, nucleic acids and lipids – which either partition into the bottom phase or precipitate  at the interface. Then, the top phase – from this first extraction step – is mixed with a given quantity of PEG6000 in  order to induce the formation of a new aqueous two phase system in which the back extraction of both  zymogens takes place. This second stage allows to obtain a mixture of both zymogens highly pure (∼=  95%)  in a bottom phase with low PEG concentration (3.70%, w/w) and therefore suitable for being used in  ultiple applications.∼=  95%)  in a bottom phase with low PEG concentration (3.70%, w/w) and therefore suitable for being used in  ultiple applications.