as phycobiliproteins (McCandless
and Craigie 1979; Nakamura and Ikawa 1993). This
difficulty was overcome by introducing the aqueous twophase
partitioning system using PEG and AS which was
developed by Iwamoto and Shiraiwa (2005) to eliminate
inhibitory substances from the crude enzyme preparation.
As a result, specific activity was elevated eightfold by AS
precipitation and the aqueous two-phase partitioning method
(Table 2) and the enzyme solution became clear with a
decrease in viscosity (data not shown). The Blue Sepharose
CL-6B affinity chromatography greatly contributed to the
tenfold improvement of the purification ratio. After MonoQ
anion exchange chromatography and Superdex 200 HR gel
filtration chromatography, the specific activity increased by
about 1,000-fold to 92.71 μmol−1 min−1 mg protein−1 with
5% recovery of the activity (Table 2). Because the apparent