# Vmax, Km: Calculation of Kinetic Constants, first order

The initial velocity of an enzyme catalyzed reaction was measured at a serious of different initial substrate concentrations in the table. Find Km (sometimes called Ks)(the half velocity constant) and ...there is moreshow problemThe initial velocity of an enzyme catalyzed reaction was measured at a serious of different initial substrate concentrations in the table. Find Km (sometimes called Ks)(the half velocity constant) and max velocity Vmax. Over what substrate concentration rane would you expect reaction to approximately follow first order kinetics (i.e) V=(k first order) [S] and estimate k-first order

Units of [S] is M Velocity (V) in micromoles/liter-min

8.35 E-6 13.8

1.0E-5 16.0

1.25 E-5 19.1

1.67 E-5 23.8

2.0 E-5 26.7

2.5 E-5 30.8

3.3 E-5 36.2

5.0 E+5 44.5

1.0 E-4 57.2

2.0 E-4 66.7

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I know that at lower substrate concentrations, the reaction follows first order kinetics.

V= (Vmax[S])/(Km+[S])

Linearizing,

1/V= (Km/Vmax)(1/[S])+1/Vmax, this is Lineweaver Burk Double Reciprocal Plot

This is of form y=mx+b

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Please show a detailed solution, even the minor math. Thank you Mr. Allen.

https://brainmass.com/chemistry/chemical-kinetics/vmax-km-calculation-of-kinetic-constants-first-order-148279

#### Solution Preview

The first thing we do is transfer the data into Excel.

Please see attached Excel file.

Make sure that all of your numbers are transferred correctly and you haven't transposed the numbers wrong. For example, one of your data points is incorrect (the number 5.0 E+5 should be 5.0 E-5.) What I did was transfer the [S] data as regular numbers and then told Excel to format those cells so that the numbers would be displayed using scientific notation. That way I ensure I have transferred the data correctly.

Next thing you do is create columns B and D which will invert the data so you end up with reciprocal, i.e. 1/[S] and 1/Vo. I am using the variable Vo to indicate "initial velocity."

Once you've gotten reciprocal data (click on cell B2 to see how you can have Excel calculate reciprocal data automatically), then you highlight columns B1-11 and D1-11. You do this by highlight B1-11 first and then hold the Ctrl key down to highlight D1-11. If you do it correctly, you will only have highlighted the data in columns B and D. This is your "double ...

#### Solution Summary

The initial velocity of an enzyme catalyzed reaction was measured at a serious of different initial substrate concentrations in the table. Find Km (sometimes called Ks)(the half velocity constant) and ...there is moreshow problemThe initial velocity of an enzyme catalyzed reaction was measured at a serious of different initial substrate concentrations in the table. Find Km (sometimes called Ks)(the half velocity constant) and max velocity Vmax. Over what substrate concentration rane would you expect reaction to approximately follow first order kinetics (i.e) V=(k first order) [S] and estimate k-first order

Physical Chemistry Collision Theory

I have a list of terms that needs to be defined in a Physical Chemistry course. With each definition I need an example for each term, as a description to it or so

term Chapter

collision theory

transition state theory

rate constant

Arrhenius equation

integrated rate law

rate law

activation energy

pseudo first order

preexponential factor (a)

half life

zeroth order reaction

first order reaction

second order reaction

third order reaction

method of initial rates

isolation method

reaction profile

collision frequency

reaction coordinate

flash photolysis

stopped flow experiment

temperature jump experiment

elementary reactions

consecutive reactions

unimolecular reactions

molecularity

steady state approximation

rate-determining step

diffusion-controlled limit

Homogeneous catalyst

catalyst

heterogeneous catalyst

Michealis- Menten kinetics

KM Michealis constant

Maximum Turnover number

Maximum Velocity

Line-Weaver-Burke Plot

Woolf Plot

Eadee-Hofstee Plot

Competitive inhibitor

Non-Competitive Inhibitor

Uncompetitive Inhibitor

Chain Reaction

Inhibition Step

Termination Step

Retardation Step

Branching Step