> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/library-preparation/dna-library-prep/library-preparation-dna-library-prep-faq-list/000005831.md).
# How does the Illumina/Nextera tagmentation enzyme make sure that both p5 and p7 adapters are added?
The tagmentation enzyme used by Illumina is pre-loaded with both read 1 and read 2 DNA oligo tags in a DNA-enzyme complex which makes sure that sequences are added to both ends of the DNA fragmentation sites. This is the tagmentation strategy which is used in both bead-linked and free-solution tagmentation enzymes. Subsequent protocol steps are optimized to produce library fragments with one p5 side adapter and one p7 side adapter to allow for sequencing compatibility.
**The following kits use a free-solution transposome**
* Nextera XT
* Illumina Tagment DNA Enzyme and Buffer Kits
**The following kits use a bead-linked transposome (note that the following use different bead-linked transposome versions)**
* Illumina DNA Prep
* Illumina DNA Prep with Enrichment
* Illumina DNA PCR-Free
* Illumina RNA Prep with Enrichment (tagments double stranded cDNA)
The [bead-linked transposomes](https://www.illumina.com/techniques/sequencing/ngs-library-prep/tagmentation.html) allows for greater flexibly of input DNA amounts so that a wide range of DNA inputs can be used to achieve a consistent library size.
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| *For any feedback or questions regarding this article (Illumina Knowledge Article #5831), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000005831%20-%20Library%20Preparation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
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