Double length equals a single subunit?

Following on from the last post... it seems reasonable to check that if you get sequences thrown up by a search which are about the double the length of one subunit in a two subunit enzyme that you don't have a situation where the two subunits are actually linked. This is the situation for the nitrile hydratase from Monosiga brevicollis which can be seen to the right of the histogram in the last post. For this reason, it seems like a good idea to check out the two sequences in the n=360 and n=380 boxes. Well the one in the n=380 box is titled "nitrile hydratase regulator [Agrobacterium radiobacter K84]" and doesn't look right at all. Scratch that one. The other one is simply called GK12401 and is from Drosophila willistoni... a eukaryote like Monosiga. Looking at the GenPept file it is easy to see how the thing was given the NHase alpha coding (I have put a green line around the bit that looks like the metal binding bit of a NHase) though I am not convinced it is what it actually is or does (based on trying to align it to Monosiga NHase or an example alpha subunit from AJ270).