ABSTRACT
Transient ATP synthesized by preparations enriched with plasmatic membranes of particles from the human placenta in the presence of insulin (4 micrograms/ml) and epidermal growth factor (1 microgram/ml) within 1 min after the addition of hormones at 30 degrees C, was isolated by means of chromatography on Dowex 1 X 8. ATP was synthesized in a medium containing Tris-HCl buffer, pH 7.5, ADP, Mg2+, and Pi during NADH-dependent oxidation in the presence of cytochrome C and oxygen. The amount of ATP was 10(-9) mole/mg protein/min. Quantitative assessment of ATP in lyophilized product was carried out by means of fluorimetry (excitation wavelength--360 nm; emission wavelength--460 nm) of NADH formed during coupled enzymatic reactions involving hexokinase and glucose-6-phosphate dehydrogenase. A possible biological role of peptide growth factor-stimulated formation of transient ATP in plasmatic membranes is discussed.