Cre Recombinase is a type I topoisomerase from bacteriophage P1 that catalyzes the site-specific recombination of DNA between lox P sites. The enzyme requires no energy cofactors and Cre-mediated recombination quickly reaches equilibrium between substrate and reaction products. The lox P recognition element is a 34 bp sequence comprised of two 13 bp inverted repeats flanking an 8 bp spacer region which confers directionality. Recombination products depend on the location and relative orientation of the lox P sites. Two DNA species containing single lox P sites will be fused. DNA between directly repeated lox P sites will be excised in circular form while DNA between opposing lox P sites will be inverted with respect to external sequences.

Concentration & Storage Condition
- 1 unit/㎕, Store at -20℃.

Storage Buffer
- 15 mM HEPES, pH 8.0, 250 mM NaCl and 50% glycerol.

10x Reaction Buffer
- 500 mM Tris-HCl, pH 7.5, 330 mM NaCl and 100 mM MgCl₂.

Unit Definition
- One unit is defined as the amount of enzyme necessary to produce maximal site-specific recombination of 0.25 ㎕ Lox P containing control DNA in 30 min at 37℃ in a total reaction volume of 50 ㎕.
Maximal recombination is determined by agarose gel analysis and by transformation.

QC Tests

- Activity, exo and endonuclease activity test, SDS-PAGE purity, performance tests.