Abstract: Disclosed is a process for the preparation of deoxyribonucleases (DNases) which comprise culturing a novel transformant belonging to the genus Bacillus, collecting a cell-free extract from cells obtained during a period ranging from the late logarithmic growth phase to the initial stage of the stationary growth phase, and subjecting said cell-free extract to fractionation or separation to obtain two or more DNases each of which possessing different substrate specificity.

Abstract: The present invention relates to novel enzymes which decompose nucleic acid and are endowed with a substrate specificity recognizing specific biological deoxyribonucleic acid and cleaving specific bonds thereof to produce fragments of deoxyribonucleic acid of specific sizes and which are obtained by culturing microorganisms belonging to genus Bacillus and purifying the cell free extract thereof by such treatment as streptomycin treatment, ammonium sulfate precipitation, ion exchange chromatography, gel filtration or combination of these processes.