[Localization of DNAase activity in cyanobacterium Plectonema boryanum CALU 465].

It was shown in experiments carried out on cyanobacterium P. boryanum, that when cells are incubated in a buffer with low concentrations of nonion detergent (0.1%, Triton X-100) one can observe the DNAse activity release into the medium. The methods of supersound desintegration of cells and following gradient centrifugation of the cell-free extracts were used to obtain three fractions of the cell membranes identified by means of spectrophotometric analysis. It has been established that P. boryanum is characterised by high level of DNAse activity associated with the cytoplasmic cell membrane. As to its activity character the DNAse under study belongs to the class of nonspecific endonucleases.