Jan 1, 1976

Caffeine enhancement of digestion of DNA by nuclease S1

Mutation Research
C J ChetsangaV Boyd

Abstract

The activity of Aspergillus orzae nuclease S1 on DNA has been investigated under varying pH and metal ion conditions. Nuclease S1 was found to preferentially digest denatured DNA. With native DNA as substrate the enzyme could only digest the DNA when caffeine was added to the reaction mixture. The enzyme was more active in sodium acetate buffer (pH 4.5), than in either standard saline citrate (PH 7.0) or sodium phosphate buffer (pH 6.8). Caffeine was also found to affect the thermal stability of DNA, resulting in a melting profile characterized by two transitions. The first transition (poorly defined) was below the normal melting temperature of the DNA, while the next transition was at the normal melting temperature of the DNA, while the next transition was at the normal melting temperature of the DNA. The susceptibility of caffeine-treated DNA to nuclease digestion seems to be a result of the local unwinding that caffeine causes in the regions of DNA that melt in the first transition. This selective destabilization presumably sensitizes the unwound regions to nuclease hydrolysis. The hydrolysates of the DNA digested by nuclease S1 were subjected first to ion exchange chromatography followed by paper chromatography. The results...Continue Reading

Mentioned in this Paper

DRUG Screen Quant Caffeine
Nickel
VEPH1 gene
Quick-Pep
Ions
Citrate Measurement
Digests
Chromatography, Qualitative; Paper,2-dimensional, Analyte Not Elsewhere Specified
Copper
Ampholytes

About this Paper

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