Purified from Thermus aquaticus YT I.

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5’…T    CGA…3’

3’…AGC    T…5’

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Concentration: 8-12 u/μl

Ligation/recutting assay: After 50-fold overdigestion with the enzyme, more than 95% of the DNA fargments can be ligated and recut

Nonspecific endonucleases test: 16 hours incubation of 1 μg of DNA (dam - ) with 100 units of the enzyme at 65°C results in no unspecific cleavage product

Reaction conditions:

• 100 mM NaCl

• 10 mM Tris-HCl (pH 8.4 at 25°C)

• 10 mM MgCl 2

• 10 mM 2-mercaptoethanol

• 100 μg/ml BSA

Incubate at 65°C under parafin oil

Storage buffer:

• 300 mM KCl

• 10 mM Tris-HCl (pH 7.4)

• 0.1 mM EDTA

• 1 mM dithiothreitol

• 500 μg/ml BSA

• 50% glycerol

Storage conditions: -20°C

Absence of contaminants: 50 units of Taq I do not produce any unspecific cleavage products after 16 hours incubation with 1 μg of λ DNA at 65°C. After 10-fold overdigestion with Taq I, more than 90% of the DNA fragments can be ligated and recut with this enzyme

Heat inactivation: 80°C for 20 minutes

Note: Incubation without BSA results in 50% activity. Activity is blocked by overlapping dam methylation