enzyme reaction mechanisms

what are the five general categories of biochemical reactions?

1. make/break c-c bonds

2. internal rearrangements/isomerisations'/eliminations

3. free radical reactions

4. group transfers

5. redox reactions

what is an apoenzyme?

the form of the enzyme without the addition of a cofactor

what is a holoenzyme?

the form of the enzyme with the cofactor

what are the important cofactors of metabolism?

NAD

NADP

FMN

FAD

what is the key feature of the cofactors of metabolism?

water soluble

what is special about NAD and NADP?

they can move easily from one enzyme to another.

what does NAD+ function in?

oxidations as part of a catabolic reaction

what does NADP function in?

reductions as part of an anabolic reaction

what is the rossman fold?

conserved protein domain. site of binding for dehydrogenases that use NAD/NADP.

what does the rossman fold consist of?

stranded parallel β sheets alternating with their associated 𝛂 helices. (β𝛂β domain)

what is a double displacement mechanism?

multiple substrate reaction, where the substrates bind one after the other. second substrate cannot bind until first substrate has been released.

what is ternary structure?

a multiple substrate reaction where both substrates bind to the enzyme at the same time

what does random ternary structure imply?

no conformational change

what does sequential ternary structure imply?

the first substrate causes a structural change that allows the second substrate to bind