Well, I don't know for sure if this is one of the proprietary restriction enzymes, but they are certainly used to "digest" glycopeptides, so it most likely is one of them. Hundreds of natural ones exist, so it would not surprise me if someone like Teva might be able to generate their own proprietary versions that would do the job without infringing. But then I haven't looked at Momenta's patents regarding their enzymes. However, Teva doesn't seem to have any that apply to these kinds of mixtures (I searched patents and applications). Heck, I can't even find anything in their IP related to heparin at all. Maybe I'm doing something wrong in my search; I find that a bit odd.
Regards, RockRat