Regulation of acid and alkaline phosphatases of Cladosporium cucumerinum by inorganic phosphate

Abstract

Cladosporium cucumerinum produced multiple isozymes of extracellular acid phosphatase, in response to phosphate concentration in the medium and related to growth phase. Production of the largest, a 174 kDa molecular form, was not affected by culture conditions and this isozyme could be a constitutive enzyme. Another form, with a mol. wt of 59 kDa, was subject to phosphate repression and was secreted to the culture medium in the early phase of fungal growth. Two minor forms, which exhibited mol. wt of 389 and 562 kDa, were detected in culture filtrates at the end of exponential growth. A single 174 kDa molecular form of acid phosphatase was detected in mycelial extracts. Furthermore, two forms of alkaline phosphatase were determined in culture filtrates and mycelial extracts in response to the phosphate level in the medium. A repressible alkaline phosphatase, with a mol. wt of 174 kDa and a form which was promoted by phosphate, with a mol. wt of 98 kDa were also found.