Allosteric Enzymes "The Exception"

Memory Hack💡

I think of allo(ssss)teric and (sss)igmoidal (the similar "s" sounds) to remind me that they go together. Additionally, a sigmoidal curve looks like an "S"!

Notes

Instead of Michaelis Menten enzymes that have a hyperbolic curve, allosteric enzymes have a sigmoidal curve. 

This is because they are multimeric→ this means that they go between two states 

• T or “tense” → low affinity: If the protein is tense, it is going to have a harder time binding substrate. It needs to be relaxed so the substrate can make its way inside. 

• R or “relaxed” → high affinity 

When a substrate binds, it pushes the entire protein towards the R state. 

→ this is what makes the signmound curve! When each substrate binds, it makes the others easier to bind to.