Estriol vs Norethindrone
Mechanistic comparison of Estriol and Norethindrone based on molecular target overlap from BindingDB and ChEMBL binding affinity data.
12
Shared Targets
40%
Jaccard Similarity
40%
IDF-Weighted Similarity
Jaccard measures raw target overlap. IDF-weighted downweights promiscuous hub targets (e.g. CYP enzymes) that bind many compounds non-specifically.
Evidence Comparison
Target Overlap
Estriol and Norethindrone share 12 molecular targets based on binding affinity data from BindingDB (Kd/IC50 ≤ 10 µM) and ChEMBL. A Jaccard index of 0.400 means 40% of the combined target set is bound by both compounds. The IDF-weighted score of 0.400 accounts for non-specific binding to metabolic enzymes.
Note: High target overlap does not imply identical mechanism or therapeutic equivalence. Binding affinity, tissue distribution, bioavailability, and downstream signaling differ significantly between compounds even when they bind the same protein.