A group of enzymes removing the serine- or threonine-bound phosphate group from a wide range of phosphoproteins, including a number of enzymes that have been phosphorylated under the action of a kinase (cf. EC
3.1.3.48 protein-tyrosine-phosphatase). The spleen enzyme also acts on phenolic phosphates and phosphamides (cf. EC
3.9.1.1, phosphoamidase).