"Two forms of the pacA-encoded acid phosphatase (designated acid
phosphatases I and II) secreted by the mold Aspergillus nidulans grown in
low-Pi medium at 37^o, pH5.0, were purified to apparent homogeneity by
PAGE. The M""r of the purified enzyme forms were ca 115000 (60000) and
113000 (62000) respectively for forms I and II secreted by strain biA1 and
ca 118000 (60000) and 121000 (61000) respectively for forms I and II
secreted by strain biA1 pacA1, as determined by exclusion chromatography
(number between brackets are the M""r as determined by SDS-PAGE). All of
these purified enzyme forms showed an apparent optimum pH ranging from 6.0
to 6.5 and no deviation from Michaelis kinetics for the hydrolysis of both
p-nitrophenylphosphate and @a-naphthylphosphate. Heat inactivation at 60^o
and at pH6.0 showed half-lives of 14min (k=0.033min^-^1) and 10min
(k=0.069min^-^1), respectively, for the purified acid phosphatases I and II
secreted by biA1 strain and half-lives of 0.8min (k=0.92min^-^1) and 0.6min
(k=0.95min^-^1), respectively, for the purified forms I and II secreted by
the biA1 pacA1 strain. The neutral sugar content of purified acid
phosphatases I and II secreted by strain biA1 was 48% and 37% (w/w),
respectively, whereas the content of forms I and II secreted by strain biA1
pacA1 was 18% and 11%, respectively."