Observation of tyrosine-O-phosphate in Drosophila melanogaster larvae by 31P-NMR spectroscopy

31P-NMR spectra of intact larvae and pupae of Drosophila melanogaster have been obtained at 109.3 MHz. A major resonance in these samples has been identified as tyrosine-O-phosphate. Its chemical shift reflects the hemolymph plasma pH. Upon disruption of the organisms (necessary for chemical analyses of tyrosine-O-phosphate), phosphatases rapidly hydrolyze this phosphate ester, generating inorganic phosphate and free tyrosine.