Transformed, embryonic and malignant cells give a high resolution 1H NMR spectrum which arises from lipids in the plasma membrane. Highly purified plasma membranes were prepared from human acute leukaemic T lymphoblasts (CCRF-CEM) in which the activity of the plasma membrane marker enzyme, 5'-nucleotidase, was enriched 45-fold. Triglyceride and cholesteryl ester each constituted about 4% of the total plasma membrane lipid, and were present in all subcellular membrane fractions isolated. Two-dimensional scalar correlated (COSY) NMR spectroscopy identified triglyceride as the main plasma membrane component giving rise to the NMR spectrum, while soluble non-membrane components accounted for 90% of the remaining resonances in the spectrum of intact cells
