How to determine Kd - (Apr/11/2010 )

Okay, so this is driving me crazy ... I'm writing a lab report to do with the change in calcium concentration in muscle cells. We used fluorescence techniques to determine this.

Firstly we calibrated our Indo-1 to determine the relative fluorescence over difference calcium concentrations for wavelengths of 405nm and 485nm. From the results we drew a graph of relative fluorescence VS pCa (-log) for both wavelengths.

The lecturer tells us that we need to use the "intersection between the two lines of best fit" to determine Kd. The thing is ... HOW do we use the two lines to work out Kd.

This is seriously frustrating me cos the answer is probably very easy and staring me in the face ...

ANY help will be GREATLY appreciated

Thanks in advance

Siciliana on Apr 12 2010, 02:55 AM said:

Okay, so this is driving me crazy ... I'm writing a lab report to do with the change in calcium concentration in muscle cells. We used fluorescence techniques to determine this.

Firstly we calibrated our Indo-1 to determine the relative fluorescence over difference calcium concentrations for wavelengths of 405nm and 485nm. From the results we drew a graph of relative fluorescence VS pCa (-log) for both wavelengths.

The lecturer tells us that we need to use the "intersection between the two lines of best fit" to determine Kd. The thing is ... HOW do we use the two lines to work out Kd.

This is seriously frustrating me cos the answer is probably very easy and staring me in the face ...

ANY help will be GREATLY appreciated

Thanks in advance