Thermo Scientific™ Exonuclease I (20 U/μL)

The Thermo Scientific™ Exonuclease I (ExoI) is a single-strand–specific DNA exonuclease that degrades ssDNA in a 3′→5′ direction. It sequentially releases deoxyribonucleoside 5′-monophosphates while leaving 5′-terminal dinucleotides intact, providing high specificity and control in nucleic acid cleanup.

ExoI is active in PCR buffers and is particularly effective for removing primers from PCR mixtures, making it essential for applications such as post-PCR sequencing, one-tube megaprimer mutagenesis, and single-stranded DNA cleanup. Importantly, the enzyme does not cleave dsDNA 3′-overhangs or DNA with 3′-OH groups blocked by phosphoryl or acetyl modifications, ensuring targeted activity.

Key Features

• Specific for ssDNA – Degrades single-stranded DNA in a 3′→5′ direction.
• Stepwise Degradation – Releases dNMPs, leaving 5′-terminal dinucleotides intact.
• High Compatibility – Fully active in PCR buffers.
• Controlled Specificity – Does not act on blocked 3′-OH ends or dsDNA overhangs.
• Efficient Cleanup – Ideal for post-PCR primer removal and ssDNA degradation.

Applications

• Primer removal from PCR mixtures:
  • Prior to sequencing PCR products
  • For one-tube "megaprimer" PCR mutagenesis
• Removal of ssDNA containing a 3′-OH terminus from nucleic acid mixtures
• Assays for detecting the presence of ssDNA with 3′-hydroxyl ends

Technical Specifications

Ordering Information

The Thermo Scientific™ Exonuclease I is a highly specific ssDNA degradation enzyme optimized for primer removal, post-PCR sequencing, and mutagenesis workflows. Its activity in PCR buffers, combined with its inability to act on dsDNA or blocked 3′ ends, makes it a reliable and efficient cleanup reagent for molecular biology laboratories.