> Hi -
>
> A RDKit-based implementation of the QED measure as described by 
> Richard Bickerton (Nature Chemistry, 2012, 4, 90-98) has been 
> implemented and made available  for download from our website ( 
> www.silicos-it.com > Biscu-it).
>
> Regards,
> - Hans
>
>


Hi Hans,

Thanks for the implementation!

Why did you use your own 11 smarts for hydrogen bond acceptors instead of 
rdkit's CalcNumHBA or NumHAcceptors 
($([O,S;H1;v2]-[!$(*=[O,N,P,S])]),$([O,S;H0;v2]),$([O,S;-]),$([N;v3;!$(N-*=!@[O,N,P,S])]),$([nH0,o,s;+0]))?
I compared your implementation with PipelinePilot and rdkit, and it correlates 
better with PP (r^2=0.978) than rdkit (0.916). Maybe Greg you can comment on 
this?
(In PipelinePilot, HBA is described as "number of heteroatoms (Oxygen, 
Nitrogen, Sulfur, or Phosphorus) with one or more lone pairs, excluding atoms 
with positive formal charges, amide and pyrrole-type Nitrogens, and aromatic 
Oxygen and Sulfur atoms in heterocyclic rings")

On your website, you mention that "discrepancies can be noted in the results 
from the logP calculations"; I agree that the end result won't be much 
different using MolLogP vs. ALogP.
But to be consistent I collected the structures of the 771 drugs mentioned in 
the original publication, calculated their MolLogP using rdkit, and fitted the 
binned distribution using the described approach.
700 compounds out of 771 gave the same ALogP as listed in the original paper 
(i.e. same structure), however for the 71 remaining drugs some discrepancies 
were observed, maybe due to different structures (I collected them from 
PubChem) or a different version of Pipeline Pilot (I used version 8.5).
I ended up with a bin size of 0.97 and the following parameters:
a       0.486849448
b       186.2293718
c       2.066177165
d       3.902720615
e       1.027025453
f       0.913012565
Dmax    145.43148

Feel free to use them!

Best,

Grégori

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