# from cathal

This was from Cathal Garvey a while back:

    (02:43:38 PM) Cathal Garvey: Here, this enzyme: Terminal Transferase and easily removed blocking groups on NTP washes = Easy homebrew DNA synthesis reaction? http://en.wikipedia.org/wiki/Terminal_deoxynucleotidyl_transferase
    (02:44:13 PM) Cathal Garvey: In other words, not so dissimilar to the existing method, but without requiring the chemistry of actually joining nucleotides with such care. In fact, you could probably do something like this:
    (02:44:21 PM) Cathal Garvey: Oligo annealed to solid substrate
    (02:44:29 PM) Cathal Garvey: Ends not phosphorylated at beginning of each step.
    (02:45:09 PM) Cathal Garvey: Add a kinase to prime DNA, add NTP + TDT
    (02:45:32 PM) Cathal Garvey: Interesting stuff!
    (02:45:44 PM) Cathal Garvey: I love all the little methods devised by nature for this function
    (02:45:49 PM) Cathal Garvey: By the way, my error there:
    (02:46:06 PM) Cathal Garvey: the method I suggest is based on the assumption that the enzyme might bind the oligo end and await an NTP,
    (02:46:16 PM) Cathal Garvey: and that you can use NDPs rather than NTPs
    (02:46:35 PM) Cathal Garvey: so that it won't polymerise further than a single nucleotide without a step involving kinase
    (02:47:06 PM) Cathal Garvey: So you can use two enzymes and NDPs in washes, if that prior assumption regarding the enzyme holds.
    (02:47:15 PM) Cathal Garvey: Which is, of course, a huge achilles heel.

## more recent

This is from Cathal more recently: "I have a concept that's only use enzymes, DNA and triphosphates. Hoping to try it someday soon for a POC."

# related igem projects

* [oligonucleotide synthesis using Terminal Deoxynucleotidyl Transferase (TdT) as an alternative to phosphoramidite-based DNA synthesis](http://2014.igem.org/Team:Cooper_Union/TdT_project)
* [DNA synthesis: characterization of Terminal Deoxynucleotidyl Transferase as an alternative oligonucleotide synthesis method](http://2014.igem.org/Team:Rutgers)