Unusual phosphatase activity resistant to SDS and pronase treatments in Xenopus ovary

An unusual phosphatase, which is resistant to treatment by 5% SDS and prote olytic enzymes, was isolated as two types, 1 and 2, from pronase-treated ho mogenates of Xenopus ovary. The molecular sizes of types 1 and 2 were estim ated as about 140 kDa and more than 2 x 10(4) kDa, respectively, by gel fil tration, but as 140 and 130 kDa as a catalytic unit, respectively, by elect rophoresis, implying that whereas type 1 might be composed of catalytic uni t alone, type 2 is a multicomponent complex consisting of a 130-kDa catalyt ic unit. Both activities were sensitive to nucleases but resistant to teste d proteolytic enzymes. These findings suggest that the unusual phosphatase activity is attributable to a polynucleotide. (C) 1999 Academic Press.