[Molecular characteristics of beta-galactosidase secreted by Penicillium canescens]

Extracellular beta-galactosidase from P. canescens culture medium was purified by ion-exchange chromatography on DEAE and CM-Sepharose CL-6B and gel filtration. The enzyme active form was shown to be a monomer with a molecular weight of about 120 kDa; the isoelectric point is 6.7 and the sedimentation coefficient is 6.5. In terms of physico-chemical and catalytic properties, the purified enzyme is similar to beta-galactosidases of other fungi of genus Penicillium. The amino acid composition and the NH2-terminal sequence of 24 residues non-homologous to the corresponding sequences of bacterial and yeast beta-galactosidases were determined.