between the surface hydrophobic groups as the
protein concentration is increased. A maximum of about 39%
of the protease activity present in the latex was precipitated
with ammonium sulfate at an initial protein concentration of
40 mg/ml. The second precipitation step provided significantly
lower recovery of protease activity but with a relatively enriched
papain fraction. The maximum purity of papain (>89%) was
achieved by limiting the protein concentration during the
second precipitation to 6 mg/ml (Table 1).