The thawed latex was mixed with wat

The thawed latex was mixed with water and pH adjusted using 6M HCl.
For extraction in aqueous two-phase system, defined amounts of solid PEG and
(NH4)2SO4 were added to the latex preparation (30 g), and the total mixture was
made up to 50 g with water. When studying the effect of pH on protease/papain
partitioning, the latexwas adjusted to the desiredpHusing 6MHCl or 6MNaOH
solutions prior to mixing with the phase components. The mixture was then
gently shaken for 15 min. The two phases were separated by centrifugation at
9000×g for 30 min at 4 ◦C. Aliquots of the phases were taken for determination
of protein concentration and protease activity. For calculation of protease activity
in the two phases, volumes of the respective phases were taken into consideration.
The presence of papain was verified by cathodic gel electrophoresis and FPLC.