L' Eomot Inversé (3/26/2012)
If there's a genetic chemistry biologist amongst the readers, maybe he can tell us what sspI stands for when it's a restriction enzyme - I can't, I don't understand that stuff at all: the molecular structure of anything more complex that aniline is way beyond the ken of anyone like me, and I don't know what any of it's called (I can just about remember what RNA stands for on a good day, or even DNA on a very good day).
Restriction enzymes cut DNA at a specific sequence of nucleotide bases, in this case, AATATT. They're used to isolate the whole gene from the rest of the genome, usually so it can be produced in large amounts via Polymerase Chain Reaction (PCR). From here, the manufactured genes can be spliced back into the genomes of other yeast cells in great number, creating your own little sspI protein-generating mass production factory.
The sspI restriction enzyme is so named because it's used to cut the sspI gene from the genome. The gene itself appears to encode for a spore protein in yeast.