Table 2. Definition of the properties measured on the protein molecular surface.

No.		Property	Symbol	Method of calculation	Units
1. Global properties
1.1	Molecular weight		Mw	PDB	Da
1.2	Total number of atoms		Na	PDB	-
1.3	Total number of residues		Nr	PDB	-
1.4	Total probed area		A	Connolly	Å2
1.5	Volume		V	Eq. 2	Å3
1.6	Shape factor		V/A	Eq. 2	Å
1.7	Total positive charge		PC_t	Connolly upgrade	e
1.8	Total negative charge		NC_t	Connolly upgrade	e
1.9	Total hydrophilicity		Phi_t	Connolly upgrade	kcal mol-1
1.10	Total hydrophobicity		Pho_t	Connolly upgrade	kcal mol-1
1.11	Total positively charged area		A_pc	Connolly upgrade	Å2
1.12	Total negatively charged area		A_nc	Connolly upgrade	Å2
1.13	Total hydrophilic area		A_phi	Connolly upgrade	Å2
1.14	Total hydrophobic area		A_pho	Connolly upgrade	Å2
2. Property surface densities
2.1	Positive charge density		PC_d	PC_t/A	e Å-2
2.2	Negative charge density		NC_d	NC_t/A	e Å-2
2.3	Hydrophilic density		Phi_d	Phi_t/A	kcal mol-1Å-2
2.4	Hydrophobic density		Pho_d	Pho_t/A	kcal mol-1Å-2
3. Property specific densities
3.1	Positive charge specific density		PC_sd	PC_t/A_pc	e Å-2
3.2	Negative charge specific density		NC_sd	NC_t/A_nc	e Å-2
3.3	Hydrophilic specific density		Phi_sd	Phi_t/A_phi	kcal mol-1Å-2
3.4	Hydrophobic specific density		Pho_sd	Pho_t/A_pho	kcal mol-1Å-2