Gene pacA+ codes for the multiple active forms of Pi-repressible acid phosphatase in the mould Aspergillus nidulans

The acid phosphatase secreted by the biA1 strain of the mould Aspergillus nidulans was separated into at least nine isoforms by isoelectric focusing (IEF). The components visualized by activity were predominantly acidic proteins with isoelectric points ranging from pH 4.0 to 6.5. Almost the same isoforms were secreted by strains pabaA1 and palD8 biA1. Furthermore, the isoforms secreted by strain pacA1 biA1 were not visualized by staining after IEF, indicating that these isoforms are encoded by gene pacA. Treatment of the secreted enzyme with endoglycosidase H also reduced the number of isoforms visualized by staining after IEF and enhanced the R_f (electrophoretic mobility) value of this enzyme visualized after PAGE.