Alkaline phosphatases of Neurospora crassa. Part I

Abstract

The presence of two alkaline phosphatases in mycelial extracts of Neurospora crassa is demonstrated. The two enzymes differ in molecular weight, electrophoretic mobility, and their response to some cations. Neither enzyme is identical with the phosphatase, repressible by inorganic phosphate, known to be present in Neurospora. Both enzymes have an absolute requirement for Zn2+, which is tightly bound to the protein and cannot be replaced by any other ion tested, and for Mg2+, which is loosely bound and can be at least partially replaced by several other ions. The possibility that the two activities represent different states of aggregation of the same subunits rather than two different proteins is discussed.