Gateway® LR Clonase® enzyme mix contains Int (integrase), IHF (integrating host factor) and Xis (excisionase) A proprietary blend of enzymes that catalyze in vitro recombination between an entry clone (containing the target gene with attL site) and a destination vector (containing attR site) to generate expression clones. We offer LR Clonase Enzyme Mix in different strengths, depending on your application and required specifications. LR Clonase II Plus enzyme mix is a newer version that provides the higher recombination efficiencies available (Table 1) and is specifically optimized for single and multi-fragment cloning (Table 1). LR Clonase II Plus Enzyme Mix is delivered as an optimized single mix of enzyme and reaction buffer, ensuring enzyme stability and ease of use in a few pipetting steps for single and multi-fragment cloning. LR Clonase II Enzyme Mix is also available as a single mix, the original LR Clonase® enzyme is enzyme and buffer in separate tubes