[Nescafe]

Hi,

Not sure if anyone is familiar with the calculations behind this instrument but I sure hope someone does!

So from the plot of RU v.s. time the software calculates kobs and koff. To me the equations used look like those for first order rate. For instance

RUt = RUmax e^-kobst

Where RUt is the response unit at time T, RU max is response unit at plateau and t is the total time during the binding experiment.

This equation is very similar to [A] = [A]o  e^-kt.

So I am wondering how does it actually calculate kobs, by plotting RUt v.s. Time where the slope of the curve would be kobs?

RUt = RUmax e^-kobs*t

lnRUt = lnRUmax - kobs*t

Anybody know if what I am saying makes any sense?

Nescafe.

[curiouscat]

Anybody know if what I am saying makes any sense?

I don't know about the others but it'd help if you clarified notation.

What's SPR? RU? kobs? koff?

Maybe these are well-known to Biochemists? If so, pardon my ignorance.

[Nescafe]

Anybody know if what I am saying makes any sense?

I don't know about the others but it'd help if you clarified notation.

What's SPR? RU? kobs? koff?

Maybe these are well-known to Biochemists? If so, pardon my ignorance.

Surface plasmon resonance, Response units, observed rate constant and rate of dissociation or the off rate

[Yggdrasil]

The software probably uses standard non-linear least squares fitting to fit the exponential functions to the RU vs time curve.  You could certainly linearize the equations as you said and calculate the rate constants by hand, but using the least squares fitting algorithm is probably the more accurate way of analyzing the data.