Deoxyribonuclease I from bovine pancreas (C15-1290-422)

General description

DNase I, or Deoxyribonuclease I, is an endonuclease isolated from bovine pancreas.

• Our DNase I Digests double str and single stranded DNA into oligo and mononucleotides.
• Bovine pancreatic DNase exists as four isozymes, having isoelectric points for A, B, C and D: 5.22, 4.96, 5.06 and 4.78.3. The predominant form is A, with smaller amounts of B and C, and only minor amount of D.
• DNase I structure resembles the structure of to exonuclease III. It includes two central ß sheets. Each β sheet is composed of six β-strands. This complex of β sheets is surrounded by extensive loop and α-helical regions. This enzyme shares structural similarity to exonuclease III.^[1]

Application

• Decreases viscosity providing better yields by removing DNA in primary cell isolation:
• Incorporating labelled bases into DNA: DNA nick
• Radioactive labelling
• Bioprocessing applications: DNA removal
• Eliminating genomic DNA from RNA preparations before RT-PCR
• In vitro transcription
• Nick translation
• DNase footprinting
• Actin regulation of actin polymerization in cells, and cell apoptosis
• UV crosslinking of proteins to nucleic acids
• DNase play a role in the regulation of actin polymerization in cells and is involved in apoptosis process ^[1]

Used for the removal of DNA from protein samples.

Biochem/physiol Actions

DNase I is an endonuclease that acts on phosphodiester bonds adjacent to pyrimidines to produce polynucleotides with terminal 5′-phosphates. In the presence of Mg²⁺, DNAse I cleaves each strand of DNA independently and the cleavage sites are random. Both DNA strands are cleaved at approximately the same site in the presence of Mn²⁺. Divalent cations such as Mn²⁺, Ca²⁺, Co²⁺, and Zn²⁺ are activators of the enzyme. A concentration of 5 mM Ca²⁺ stabilizes the enzyme against proteolytic digestion. The pH optimum is found to be between 7 and 8. DNAse I from bovine pancreas consists of four chromatographically distinguishable components, A, B, C, and D, with their molar ratios being 4:1:1 respectively. Only minor amounts of D are found. 2-Mercaptoethanol, chelators, sodium dodecyl sulfate (SDS) and actin are known to inhibit the enzyme activity.

Features and Benefits

Our Deoxyribonuclease DNAse I,is essentially RNAse free product, which support the product application.

Unit Definition

One Kunitz unit will produce a change in A₂₆₀ of 0.001 per min per mL at pH 5.0 at 25 °C, using DNA, Type I or III, as substrate.

Physical form

Crude preparation, contains calcium chloride

Preparation Note

10 mg/mL solution of DNAse I in 0.15 M NaCl may lose <10% of its activity when stored for a week in aliquots at −20 °C. The same solutions stored in aliquots at 2-8 °C can lose approximately 20% activity. It remains active for up to five hours at 60 °C between pH 5 and 7, and loses activity in <10 minutes at 68 °C. It loses activity at the rate of 6%/hour in acetate buffer (pH 5.0) and tris buffer ((pH 7.2) at 1 mg/mL concentration.

Analysis Note

Protein determined by biuret.