Anyone Good in Chemistry??

[BiochemC]

Please help with this question!

I'm not good at calculations, but i found the Vmax through my graph,

vmax=0.909 or 1/Vmax=1.10

 

question: if the enzyme has a molecular weight of 56,000 and was present in the assays above at a concentration of 4.5ug/ml, calculate the turnover number and the enzyme efficiency in the absence of ethanol.

 

i know Kcat= Vmax/[Etotal] however i dont know how to calculate the etotal, this may be simple math, but i'm a 4th year bio student, and my chem is rusty!

thanks