# Homework Help: MCQ- Enzyme kinetics

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1. Apr 28, 2017

### Tyto alba

1. The problem statement, all variables and given/known data
An enzyme catalysed reaction becomes zeroth order when:

a.The velocity of enzyme action very low
b. The velocity of enzyme action very high
c.Enzyme conc very high
d. All of these

The attempt at a solution
I understand An enzyme mediation recation becomes Zeroth order if [ S]>>Km where Km= [ S] when Vo=Vmax/2.

I really have no idea what way I should approach this MCQ.

2. Apr 28, 2017

### epenguin

Well unless there is excess substrate inhibition, then for any given concentration of enzyme the reaction velocity is as high as it can be when [ S]>>Km, and I think you should answer b and not worry about it because you are getting some rather bad questions. The zero order is related strictly not to the velocity, but to the substrate concentration as you realise.

Last edited: Jun 11, 2017