[ccp4bb] different Kd and Km value

2015-02-26 Thread Srivastava, Dhiraj 
Hi
   I have a protein with two substrate. when I am doing the binding studies 
with the two substrate separately, I am finding one of the substrate to have 
similar kd and Km. however the km and kd values are almost 30 fold different 
for the other substrate. it binds 30 fold more tightly then you can think based 
on Km. I don't know how to explain this. Km and Kd can be different but does 
any one have seen that much difference in Kd and Km?


Thank you
Dhiraj

Re: [ccp4bb] different Kd and Km value

2015-02-26 Thread William G. Scott 
 On Feb 26, 2015, at 4:51 PM, Srivastava, Dhiraj dhiraj-srivast...@uiowa.edu 
 wrote:
 
 Hi
   I have a protein with two substrate. when I am doing the binding studies 
 with the two substrate separately, I am finding one of the substrate to have 
 similar kd and Km. however the km and kd values are almost 30 fold different 
 for the other substrate. it binds 30 fold more tightly then you can think 
 based on Km. I don't know how to explain this. Km and Kd can be different but 
 does any one have seen that much difference in Kd and Km?
 
 
 Thank you
 Dhiraj

If k+2 isn’t small compared to k-1, Km cannot be approximated by Kd.