[sule21]

hi everyone, i'm new to this forum so please don't lambast me for asking a possible stupid question, but here it goes:

i've got a lab report for Chemical Kinetics, and i need help with plotting a Lineweaver-Burke graph to determine the Vmax and 1/V for 6 assays of tyrosine conversion to melanin. 

from my spectroscopy readings, for one of my assays, i've been given:

slope = Km/Vmax = 0.1128 (from absorption vs. time plot)
intercept of absorption vs. time plot = 0.236
t = 444s
= 7.39x10^-4 mol/L

how to i take this information and get a value for 1/V???

we're supposed to calculate the theoretical value of V from Km and Vmax given on our formulated Lineweaver-Burke plot, and the from our experiment...

am i just using the equation:

1/V = Km/Vmax x 1/ + 1/Vmax

i plugged in the slope (Km/Vmax) and the 1/, but how do i get my values for 1/V and 1/Vmax?



also....could i get my desired values if i just take my slopes and put them in a 1/V vs. 1/ graph, and extrapolate? b/c i've tried that and my line isn't straight, even though its supposed to be...

HELP

[Yggdrasil]

What raw data are you measuring to get these values?

[sule21]

slope = Km/Vmax = 0.1128 (from absorption vs. time plot)
intercept of absorption vs. time plot = 0.236
t = 444s
= 7.39x10^-4 mol/L (concentration of tyrosine off the bottle)

this is the information i've acquired from the lab for one assay

[Yggdrasil]

slope = Km/Vmax = 0.1128 (from absorption vs. time plot)
intercept of absorption vs. time plot = 0.236
t = 444s
= 7.39x10^-4 mol/L (concentration of tyrosine off the bottle)

this is the information i've acquired from the lab for one assay

The slope of your absorption v. time plot will not be Km/Vmax.  The slope of this plot is your V.  Km/Vmax is the slope of the Lineweaver-burke plot (which plots the 1/V vs 1/ for many reactions).

[sule21]

slope = Km/Vmax = 0.1128 (from absorption vs. time plot)
intercept of absorption vs. time plot = 0.236
t = 444s
= 7.39x10^-4 mol/L (concentration of tyrosine off the bottle)

this is the information i've acquired from the lab for one assay

The slope of your absorption v. time plot will not be Km/Vmax.  The slope of this plot is your V.  Km/Vmax is the slope of the Lineweaver-burke plot (which plots the 1/V vs 1/ for many reactions).

thanx....i figured it out....albeit, after pulling an all-nighter trying every which way possible

i guess sleep is more important than i thought  when trying to focus and study