The electrophoresis patterns indicated that papain still contained
the contaminating proteases, chymopapain and chitinase
after the two-step salt precipitation procedure (Fig. 1, lane 3),
as also observed earlier by Kimmel and Smith [4] and Baines
and Brocklehurst [6]. The processing time of this experiment
was however faster than that in the earlier reports. Earlier studies
have shown that chymopapain-free papain could be obtained
by crystallization after the two-step salt precipitation, however
only at a defined concentration of latex used for purification [6].