I made the mistake of googling it and what comes up is that it's a "ship name" relating to a couple of boys in a band. At least, on the internet it is. Bleah.
Aside from that, it strikes me as synthetic and fictiony - kind of like Renesmee, Arrietty, Danaerys, or Katniss, and about as usable.
It also reminds me of the words American, Marrakesh, and meerkat.
For
Mary Katherine, Marikat could be created and would seem less forced IMO.
- mirfak