Open AccessAn Intracellular Endonuclease of Bacillus subtilis Specific for Single‐Stranded DNA
Author(s) -
CIARROCCHI Giovanni,
FORTUNATO Adriana,
COBIANCHI Fabio,
FALASCHI Arturo
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10043.x
Subject(s) - bacillus subtilis , endonuclease , dna , enzyme , biochemistry , extracellular , sephadex , intracellular , biology , deoxyribonuclease , chemistry , mode of action , microbiology and biotechnology , bacteria , genetics
We have fractionated from extracts of Bacillus subtilis the DNase activity specific for singlestranded DNA; the activity separates in two main fractions on Sephadex G‐200, a larger one (M r < 4) and a smaller one (M r ∼ 30000). We have purified the smaller, more abundant fraction nearly 3000‐fold. The purified enzyme has a pH optimum close to 8, is activated by Ca 2+ , and is inhibited by EDTA; the enzyme hydrolyses single‐stranded DNA at a rate approximately 40 times greater than double‐stranded DNA. The mode of action is endonucleolytic on both substrates. but the possibility that the two activities may reside on different molecules is not ruled out. The products have 5′‐P and 3′‐OH ends. The enzyme is different from those purified from the culture media of the same organism in several respects; the latter are all extracellular enzymes, they are not specific for single‐stranded DNA (except one) and have all an exonucleolytic mode of action.