An E. coli strain that carries the cloned and modified SpeI gene from Sphaerotilus species (ATCC 13923). High Fidelity (HF?) Restriction Enzymes have 100% activity in CutSmart? Buffer; single-buffer simplicity means more straightforward and streamlined sample processing. HF enzymes also exhibit dramatically reduced star activity. HF enzymes are all Time-Saver? qualified and can therefore cut substrate DNA in 5-15 with the flexibility to digest overnight without degradation to DNA. Engineered with performance in mind, HF restriction enzymes are fully active under a broader range of conditions, minimizing off-target products, while offering flexibility in experimental design.