Superoxide-producing thermostable complex from plant foods: isolation, purification and properties

Abstract

From Armenian plant food – tomato (Solanum lycopersicum esculentum), carrot (Daucus carota subsp. sativus), green bean (Phaseolus vulgaris) and potato (Solanum tuberosum), the isoforms of superoxide (О2) producing complexes between NADPH containing protein component (NPC) and Fe(III) – NPC-Fe(III), were isolated and purified for the first time. At the same time, the fractionation of these complexes at pH 9,5 and 4,8 were carried out [1]. The isoforms of NPC-Nox are high thermostable biosystems (up to 100oC). The immediately mechanism of the production of О2 by these complexes, due to the transfer of the electron from NPC to the Fe(III), then to О2 for its reduction up to О2 was conditioned. As a substrate for NPC-Fe(III) is not free NADPH, but NADPH is connected with the protein component (PC). The forms of optical absorption spectra of these complexes in visible region essentially were differed, although, in UV region the characteristic for the proteins maximal optical absorption at 260-280 nm were observed. The higher specific content (mg/g) for complexes from tomato, than from carrot, green bean and potato were observed. The direct proportional dependence between the content of the NADPH in the composition of NPC and stationary concentration of produced О2 in homogenous phase (in solution) and gas phase were presented. The isolated NPC from indicated above complexes, at the expense of NADPH, only the reductive (antioxidant) effect was indicated and was activated the NADPH oxidase (Nox) in vitro, in particular from erythrocytes membranes (ЕМ) аnd leukocytes membranes (LM). By the blowing of the slightly opalescent aqueous solutions of these complexes with oxygen the gas phase О2 were produced, which were transferred oxygen through the silicone or glass tubes.