title: Specificity of the S1 nuclease from Aspergillus oryzae.
abstract: Conditions are described for digesting single-stranded DNA by S1 nuclease without introducing breaks in double-stranded DNA. The enzyme is inhibited by low concentrations of various compounds of phosphate. Under certain conditions S1 nuclease cleaves the strand opposite a nick in bacteriophage T5 DNA; under other conditions, the enzyme cleaves a loop in one strand of heteroduplex lambdaDNA while leaving the opposite strand intact. S1 nuclease makes many single strand breaks in ultraviolet-irradiated duplex lambdaDNA. Superhelical DNA of phiX174 (Form I) is converted first to a relaxed circular molecule (Form II), and then to a linear molecule (Form III) by cleavage at one site per molecule. Since the cleavage occurs at many sites in the population of molecules, the partially single-stranded regions in phiX174 superhelical DNA are not determined by specific nucleotide sequences.
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology; D001230:Aspergillus / Q000201:enzymology*; D001236:Aspergillus oryzae / Q000201:enzymology*; D004262:DNA Restriction Enzymes; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D003851:Deoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D011756:Diphosphates / Q000494:pharmacology; D004720:Endonucleases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D010710:Phosphates / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D000227:Adenine Nucleotides; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D011756:Diphosphates; D010710:Phosphates; D003851:Deoxyribonucleases; D004720:Endonucleases; D004262:DNA Restriction Enzymes; D010727:Phosphoric Diester Hydrolases