4 nitrophenol 2 Animals 2 Enzyme Stability Eukaryota 2 Extracellular hydrolase 2 Glycerophosphocholine phosphodiesterase 2 Glycerylphosphorylcholine 2 Hydrogen-Ion Concentration 2 Kinetics Lipid metabolism 2 Lysosomal 2 Lysosomes 2 Phosphatidylcholines 2 Phosphoric Diester Hydrolases 2 Phosphorylcholine 2 Protozoa 2 Substrate Specificity 2 Temperature 2 Tetrahymena 2 Tetrahymena thermophila 2 acid phosphatase 2 article 2 cell free system 2 choline (4 nitrophenyl phosphate) 2 culture medium 2 degradation 2 enzyme activity 2 enzyme analysis 2 enzyme purification 2 enzyme substrate 2