You have isolated a previously unstudied protein, identified its complete structure in detail, and determined that it catalyzes the breakdown of a large substrate. you notice it has two binding sites. one of these is large, apparently the bonding site for the large substrate; the other is small, possibly a binding site for a regulatory molecule. what do these findings tell you about the mechanism of this protein?

1 it is probably a cell membrane transport protein–like an ion channel.
2 it is probably a structural protein that is involved in cell-to-cell adhesion.
3 it is probably an enzyme that works through allosteric regulation.
4 it is probably an enzyme that works through competitive inhibition.
5 it is probably a structural protein found in cartilage or skeletal tissue.