Phosphatase assays using Calf intestinal alkaline phosphatase and Lambda protein phosphatase followed by nanofluidic proteomic immunoassay (NIA) show that in rat, GP 4.96, GP 4.94 and GP 4.85 are the three phosphoforms in mature (caudal) sperm as against two phosphoforms GP 4.96 and GP 4.94 in immature (testicular) sperm.
Source: wiktionary