A single, phosphate-repressible deoxyribonuclease, DNase A, secreted in Aspergillus nidulans.
High levels of nuclease activities were identified in filtrates of Aspergillus cultures after growth in low-but not in high-phosphate media. Deoxyribonuclease activities, characterized extensively by column chromatography, showed a coincident single peak for ss- and ds-DNase which was distinct from the peak for RNase. Both ss-DNase and ds-DNase are endonucleolytic and showed the highest activity in the presence of Ca2+ and Mn2+ (at pH 8.0). They also showed identical heat sensitivities suggesting that a single, phosphate-repressible DNase was secreted. This enzyme, therefore, corresponds to the well-characterized extracellular DNase A of Neurospora. However, the Aspergillus DNase A did not cross-react with antisera to secreted Neurospora nucleases and showed different chromatographic properties, and active peptides of different sizes were visualized on DNA activity gels. The increasing derepression of Aspergillus DNase A by decreasing phosphate levels was similar to that of secreted alkaline phosphatase and these increases were both abolished by the regulatory mutant palcA.
Käfer
E
E
Department of Biology, McGill University, Montreal, Canada.
Tittler
A
A
Fraser
M J
MJ
D001233:Aspergillus nidulans / Q000201:enzymology*; D002853:Chromatography, Liquid; D003429:Cross Reactions; D003851:Deoxyribonucleases / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D004794:Enzyme Repression; D005809:Genes, Regulator; D006358:Hot Temperature; D009491:Neurospora / Q000201:enzymology; D010710:Phosphates / Q000494:pharmacology
D010710:Phosphates; D003851:Deoxyribonucleases; C019328:deoxyribonuclease A