Cytochrome P450 System May Be Involved in the Light Emission of Higher Fungi

Abstract

The paper presents data that testify in favor of the participation of the cytochrome P450 system in the light emission of higher fungi. Extracts from mycelia of different species of luminous basidiomycetes containing fungal luminescent systems that provide luminescence in vitro were obtained. Applied conditions for the isolation of luminescent systems (sonication, centrifugation at 40000g) indicate the presence of membrane structures in the extracts, in particular, microsomes formed as a result of ultrasonic disintegration of the endoplasmic reticulum (ER). Differential spectral analysis of the extracts revealed the presence of two absorption peaks at 410 nm and 450 nm, which indicates the presence of cytochromes b5 and P450. The luminescence of the extracts is stimulated by reduced pyridine nucleotides, however, the addition of NADPH causes a higher level of luminescence compared with NADH. The addition of hydrogen peroxide significantly (from several times to 1-2 orders of magnitude) increases the luminescence intensity of extracts activated by NAD(P)H. The addition of fluconazole significantly inhibits the light emission of extracts. The data obtained indicates that the cytochrome P450 system associated with ER membranes may participate in the mechanism of light emission of higher fungi with the involvement in the process of electron transport enzyme systems: NADPH-dependent reductase of cytochrome P450 - cytochrome P450 and NADH-dependent reductase of cytochrome b5 - cytochrome b5 - cytochrome P450. In this case, cytochrome P450 may hydroxylate hispidin (precursor of the luminescent reaction substrate) to form luciferin and catalyze its oxidation in the presence of ROS with light emission.