Original Article

Comparison between scatchard and dose/response ratio equations

Zheng-jun Jin, Ai-yao Yu


Scatchard equation is extensively used inreceptor dynam ics studies. This equation suffers from its high sensitivity to lo,v-reaction errors and produces an under-estimated EA max, leading to an often bewildering Hill coefficient (nH). We have shown that both Scatchard formula (S) and the dose/response ratio equation (D/R) derive from Michaelis Menton equation and are reciprocally related. Both formulae were applied in our studies of radioligand binding experiments and were equally effective as far as KD, EA max were concerned. But the D/R formula showed a better compliance with experimental data, gave usually more logical KD and EA max, and thus was a better preparatory equation to Hill coefficient. The analysis of the advantages and disadvantages of both formulae shows that in the case of a simple receptor system and ligands of the same nature, the D/R equation often leads to success while S fails. The D/R equation is very simple to use, and is especially useful when excessive experimental errors are suspected. The adjunction of the D/R equation to a standard Scatchard plot is rended in case of a negative co-operativity or the existence of receptor sub-typing, especially in ligand displacements.

Article Options

Download Citation

Cited times in Scopus