Characterization of two similar differential tumor markers based on phosphofructokinase activity arising from the influence of cancer patient serum.
The activity of phosphofructokinase (ATP: D-fructose-6-phosphate 1-phosphotransferase, EC.2.7.1.11) was found to decrease through the influence of sera from cancer patients. Two similar differential methods were developed using phosphofructokinase (PFK) as the indicator enzyme. In the original "acidic ATP method" (AAM), an acidic ATP-aqueous solution is mixed with a PFK-serum mixture following incubation at room temperature for 9 min prior to injecting a reaction cocktail without ATP into the latter. In another "two-step method" (TSM), the reaction cocktail including ATP is added to a mixture of PFK and serum after its incubation for 60-90 min at 37 degrees C. The reaction mechanism of AAM is as follows: The buffering capacity of sera decreases with the progress of malignant tumors, whose physiology is termed subdetectable acidosis, but more recently designated as hydrogen ionic stress. In contrast, TSM occurs through an increase in serum oxidation activity, causing reversible oxidation of PFK and subsequent decrease in PFK activity. Such physiology is presently termed oxidative stress [Sies S: Oxidative Stress. London: Academic Press, 1985] and recognized as an increase in active oxygens, lipid peroxides, and oxidation enzymes in the serum. These findings are based on examination of the effect of ammonium sulfate at various concentrations, dithiothreitol in a PFK suspension, antagonistic reagents, sodium azide, effects of various volumes and dilutions of serum on the PFK activity, and the clinical application of both methods. We conclude that AAM and TSM have entirely different reaction mechanisms and thus different clinical applications.
Nakamura
K
K
Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Japan.
Nakajima
Y
Y
Nakamura
Y
Y
D000136:Acid-Base Equilibrium; D000255:Adenosine Triphosphate / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000097:blood*; D002021:Buffers; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009369:Neoplasms / Q000097:blood*; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*
D014408:Biomarkers, Tumor; D002021:Buffers; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1