Star Activity Producing Extra Bands (Restriction Enzyme Digest)

Question

Accepted Answer

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) Incorrect reaction buffer used instead of enzyme-recommended buffer 2) Excessive enzyme units in reaction causing off-target cleavage 3) Glycerol concentration >5% v/v from adding >10% enzyme volume to reaction 4) Prolonged incubation time beyond minimum required for complete digestion Solutions: 1) Use the manufacturer-recommended buffer supplied with the restriction enzyme 2) Decrease enzyme units to minimum required for complete digestion 3) Ensure enzyme volume does not exceed 10% of total reaction volume (keeping glycerol ≤5% v/v) 4) Reduce incubation time to minimum required for complete digestion 5) Use High-Fidelity (HF®) restriction enzymes engineered for reduced star activity