A part of the irregularly-occurring phosphatasc activity of [male] urine is due to prostate phosphatase. Ejaculates, as well as prostate glandular tissue, are extremely rich in a phosphatase whose pH optimum (on phenylphosphate) is 4.5. Prostate phosphatase differs in specificity from ordinary urinary phosphatase, splitting [alpha]- and [beta]-glycerophos-phates equally well.