Thermostable enzyme isoforms, continuously producing monocomponent superoxide radicals, from human postoperative serous fluids: isolation and properties.

Free radicals are generated in the body through endogenous and exogenous systems, with their overproduction linked to chronic diseases such as cancer. Interestingly, chemotherapeutic drugs utilize free radicals to induce apoptosis in cancer cells, highlighting their dual nature. This study explores the therapeutic potential of free-radical-generating compounds in solid tumor treatment. Using a patented universal method, superoxide (O2-)-producing enzymatic systems were isolated for the first time from serous fluids of patients with breast cancer, gastric cancer, and liver cirrhosis. These enzymes were qualitatively and quantitatively characterized and found to continuously produce monocomponent O2- under aerobic in vitro conditions. The enzyme complexes consist of flavin adenine dinucleotide (FAD), a reduced nicotinamide adenine dinucleotide phosphate (NADPH)-containing protein component (NPC), and Fe(III) ions. Their stable O2- production mechanism was elucidated, and characteristic optical absorption and fluorescence excitation spectra were recorded. The concentrations of monocomponent O2- were quantified in moles (mol/ml) for each serous fluid type. These findings suggest that liquid-phase O2- could be used to selectively destroy cancer cells by predetermining effective concentrations. Furthermore, since O2--producing enzymes can oxidize adrenaline, they may help reduce elevated adrenaline levels in tumor cells. Future animal studies will assess their efficacy in eliminating metastatic cells, particularly in the postoperative period. This novel approach may offer a promising adjunct therapy in oncology.