And finally something called ISO enzymes or isozymes. So let's begin by focusing on allosteric control. So many of the enzymes produced inside our cells actually contain these regions. These sites we call allosteric sites. And these allosteric sites are different than the active sites found on the enzyme that binds onto the substrate molecule. So we have special types of signal molecules, regulation molecules found inside our body that can bind onto these allosteric sites found on allosteric enzymes.