I did a practical and am now trying to do the data analysis of it. the prac was the alpha-chymotrypsin catalyzed hydrolysis of 4-nitrophenyl trimethylacetate.(adsbygoogle = window.adsbygoogle || []).push({});

I have values for X, Y and B and the lab manual has asked "Using the approximated, simplified expressions for X (equation 2), Y (equation 3) and B (equation 4), determine K_{cat}, [E]_{0act}and K_{2}/K for each kinetic experiment.

From these values, determine K_{m}and p."

I have calculated K_{cat}, [E]_{0act}and K_{2}/K, but cant work out how to determine K_{m}.

the simplified equations are -

equation 2 is simplified to x ≈ K_{cat}.[E]_{0act}(if [ S] >>k_{m})

equation 3 is simplified to y ≈ [E]_{0act}(if [ S] >>K_{m}and K_{2}>>K_{3})

equation 4 is simplified to B ≈ K_{2}[ S]/K (if [ S]>>K_{m}and K_{2}>>K_{3})

where K_{cat}= K_{2}K_{3}/(K_{2}+K_{3}) ≈ K_{3}(if K_{2}>>K_{3})

K_{m}= K_{3}K/(K_{2}+K_{3})

the lab manual suggests "to determine K_{m}, consider how K_{2}/K can be derived from the expressions for

K_{cat}and K_{m}."

I'm lost and not sure how to solve for K_{m}. I have spent hours on it and just don't understand what it is I'm supposed to do.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Enzyme kinetics

Have something to add?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**