[Photodesorption of mitochondria].

A photodesorption of mitochondria absorbed on a quartz plate was found. The rate of desorption depends on the wavelength, and the intensity and time of irradiation. The maximal rate of photodesorption was detected upon ultraviolet irradiation at the absorption band of mitochondrial proteins. Probably, the photodesorption is caused by a local photothermal effect: a heating of photoexcited surface-membrane proteins, which attach mitochondria to the quartz plate. Preliminary fixation of a smear by isopropanol preserves the spontaneous desorption. No photodesorption of either mitohondria or formazan was observed upon irradiation of the smear with formazan by visible light (wavelength 540 nm; formazan was formed in the NADH-pNTV:reductase reaction). The data obtained are important for the elaboration of technology of mitochondrial immobilization in measurements of the enzyme activity and for biocensors.