Glycerophosphoryl diester phosphodiesterase hydrolyzes deacylated phospholipids to G3P and the corresponding alcohols. a sn-glycero-3-phosphodiester + H2O = an alcohol + H(+) + sn-glycerol 3-phosphate Optimum pH is 7.5. Up-regulated by low levels of phosphate in the medium. There are 2 isozymes of glycerophosphoryl diester phosphodiesterase in E.coli: a periplasmic isozyme (GlpQ) and a cytosolic isozyme (UgpQ). Belongs to the glycerophosphoryl diester phosphodiesterase family.