Appendix - Design and Use of Relational Databases in Chemistry - page 183

A.5.1 Amw
Table A.2 is a table of average molecular weights for each of the first 103
atoms in the periodic table. Because most SMILES do not contain explicit
hydrogen atoms, an additional 6 rows are included to match atoms with
1-6 implicit hydrogen atoms. The function amw defined above uses this
table to compute average molecular weight.

A.5.2 Tpsa
Table A.3 shows SMARTS for fragments described by Ertl, Rhode, and
Selzer. 2 It contains the SMARTS definition of the fragment and the frag-
ment partial polar surface area. This table is used in the tpsa function to
compute the polar surface area for a molecular structure.

A.5.3 Public166keys
Table A.4 shows commonly used fragment keys: the MACCS public166-
keys. This table is used with the public166keys function above to produce
a bit string key for use in filtering before substructure searching and for
similarity computations. The table consists of SMARTS patterns 3 used to
identify each of 166 substructures.

Table A.4 SMARTS and Bit Position for public166keys

SMARTS abit Description

[!0*] 1 ISOTOPE

[Ge,Sn,Pb,As,Sb,Bi,Se,Te,Po] 3 GROUPIVA,VA,

VIA PERIODS 4-6

[Ac,Th,Pa,U,Np,Pu,Am,Cm,Bk,Cf,Es,Fm,
Md,No,Lr]

4 ACTINIDE

[Sc,Y,Ti,Zr,Hf] 5 GROUPIIIB,IVB

[La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,
Tm,Yb,Lu]

6 LANTHANIDE

[V,Nb,Ta,Cr,Mo,W,Mn,Tc,Re] 7 GROUPVB,VIB,VIIB

[!#6]~1~*~*~*~1 8 QAAA@1

[Fe,Co,Ni,Ru,Rh,Pd,Os,Ir,Pt] 9 GROUPVIII

[Be,Mg,Ca,Sr,Ba,Ra] 10 GROUPIIA

*~1~*~*~*~1 11 4MRING

[Cu,Ag,Au,Zn,Cd,Hg] 12 GROUPIB,IIB