passages.id: split_9_validation_136_passage
passages.type: progene_text
passages.text: The dihydrosphingosine-1-phosphate phosphohydrolase activity was efficiently inhibited by excess S1P but not by lysophosphatidic acid , phosphatidic acid , or glycerol 3-phosphate , indicating that SPP2 is highly specific to sphingoid base 1 - phosphates .