Unit Definition

One unit is defined as the amount of enzyme required to protect 1 μg of λ DNA in a total reaction volume of 20 μl in 1 hour at 37°C against cleavage by BstUI restriction endonuclease.

Reaction Conditions

1X NEBuffer™ 2
Supplement with 160 µM S-adenosylmethionine (SAM)
Incubate at 37°C

1X NEBuffer™ 2
50 mM NaCl
10 mM Tris-HCl
10 mM MgCl₂
1 mM DTT
(pH 7.9 @ 25°C)

Control Protection Assay

A 20 μl reaction in NEBuffer 2 containing 1 μg of Lambda DNA, supplemented with 160 uM SAM and 1 unit of M.Sss I incubated for 1 hour at 37°C, followed by heat inactivation at 65C for 15 minutes,  results in 95% protection from digestion with 10 units of BstU I in rCutSmart buffer incubated at 60°C for 30 minutes as determined by agarose gel electrophoresis.

Storage Buffer

10 mM Tris-HCl
1 mM EDTA
200 µg/ml BSA
50% Glycerol
pH 7.4 @ 25°C

Heat Inactivation

65°C for 20 minutes