Home › Failure Case Library › Star Activity Producing Extra Bands
Restriction Enzyme Digest moderate

Star Activity Producing Extra Bands

Symptom
Extra DNA bands appear on gel beyond expected digest fragments, indicating cleavage at non-canonical recognition sequences due to relaxed enzyme specificity.
Common Causes
  1. 1 Incorrect reaction buffer used instead of enzyme-recommended buffer
  2. 2 Excessive enzyme units in reaction causing off-target cleavage
  3. 3 Glycerol concentration >5% v/v from adding >10% enzyme volume to reaction
  4. 4 Prolonged incubation time beyond minimum required for complete digestion
Solutions
  1. 1 Use the manufacturer-recommended buffer supplied with the restriction enzyme
  2. 2 Decrease enzyme units to minimum required for complete digestion
  3. 3 Ensure enzyme volume does not exceed 10% of total reaction volume (keeping glycerol ≤5% v/v)
  4. 4 Reduce incubation time to minimum required for complete digestion
  5. 5 Use High-Fidelity (HF®) restriction enzymes engineered for reduced star activity
Related Video (3)
Addgene ★ 92
Restriction Digest Analysis
"Directly shows restriction digest setup, gel analysis, and how different cut patterns/bands are interpreted, matching this failure's detection method."
New England Biolabs ★ 80
Cloning With Restriction Enzymes
"Explains how to choose and use restriction enzymes correctly, the key context for avoiding buffer/condition errors that cause star activity."
Bilibili (China-Accessible Mirrors) ★ 58
Hands-on plasmid construction guide
"Comprehensive hands-on plasmid construction protocol that includes restriction digest steps, giving practical technique context though not focused on troubleshooting."
Source: neb.com ↗
← Back to all cases