Studies on sheep kidney nuclease. I. An improved purification method and some properties

Area of Science:

• Biochemistry
• Enzymology

Background:

• Sheep kidney nuclease (nuclease SK) is an enzyme with specificity for single-stranded nucleic acids.
• Characterizing and purifying enzymes is crucial for understanding their biological functions and potential applications.

Purpose of the Study:

• To describe an improved purification method for sheep kidney nuclease (nuclease SK).
• To characterize the purified nuclease SK enzyme, including its molecular weight and substrate specificity.

Main Methods:

• Purification involved sequential steps: 0.85% NaCl extraction, DEAE-cellulose treatment, polyethylene glycol fractionation, phospho-cellulose chromatography, CM-Sephadex chromatography, and phospho-cellulose rechromatography.
• Enzyme identity was confirmed by comparing its properties to known characteristics.
• Molecular weight was estimated using gel filtration on Sephadex G-100.

Main Results:

• The purification method yielded an approximately 390-fold increase in nuclease SK purity.
• The purified enzyme demonstrated hydrolytic activity against heat-denatured calf thymus DNA and yeast RNA.
• No hydrolytic activity was observed against native calf thymus DNA or various adenine nucleotides (ADP, ATP, AMP, cyclic AMP).

Conclusions:

• The developed method significantly improves the purification of sheep kidney nuclease (nuclease SK).
• The purified enzyme exhibits properties consistent with previous reports and is specific for single-stranded nucleic acids.