Coupled Enzyme Reactions

These are actually quite common in molecular biology. They are used because often reactions don't produce a conveniently colored product, so they are not easily measurable. Thus, we add steps. Usually, we try to keep the number of steps down, though, because more complexity means more things that can go wrong.

Reaction I: A + B -> C + D, in the presence of enzyme 1
Reaction II: C + E -> F + G, in the presence of enzyme 2

A, B, C, D, E, F, enzyme 1, and enzyme 2 are all colorless. If you only had A, B, and 1, there would be no way to tell that a reaction is occurring. By adding E and enzyme 2 to your tube, you create a condition where enzyme 1 working allows enzyme 2 to work and make color. Since color cannot happen without the reaction I, you can now track it. This is a basic schema for a coupled reaction.

This is the current plan in my research as well. We have an A, B, C, D, E, G, 1, and 2 that are clear. Actually, so is F in the visible range. It is colorful in the UV range, which we poor humans can't see but our machine can, so as far as we are concerned, it is "colorful enough."

Next problem: We don't have any enzyme 2. We can't buy it because nobody makes it. We shall have to request some enzyme-2-making-cells from a lab that studies it, and extract the enzyme ourselves.

Let's do this thing!