fig5

Figure 5. Correlations between maximum steady-state ATP hydrolysis rate and affinity in mouse embryo fibroblast membranes. (A): ln(V₁) vs. the free energy of binding, . The maximum steady-state ATP hydrolysis rate, V₁, is expressed as a percentage of the basal steady-state ATP hydrolysis rate taken as 100%. Data were obtained from phosphate release measurements: (1) amitriptyline, (2) chlorpromazine, (3) cis-flupenthixol, (4) cyclosporine A, (5) daunorubicin, (6) dibucaine, (7) diltiazem, (8) glivec, (9) lidocaine, (10) OC144-093, (11) progesterone, (12) promazine, (13) reserpine, (14) trifluoperazine, (15) trifluopromazine, (16) PSC 833, (17) vinblastine (1-17, from Ref.^[78]), (18) amlodipine, (19) nimodipine, (20) verapamil (18-20, from Ref. ^[93]), (21) sirolimus, (22) tacrolimus (21-22 from Simon Lang and A.S., unpublished results), (23) tariquidar (X. Li-Blatter and A.S., unpublished results), (24) etoposide (from Ref.^[66]), (25) C₁₂-maltoside, (26) C₁₃-maltoside, (27) C₁₂EO₈, (28) Triton X-100, (29) Tween 80, (30) C₁₀-TAC, (31) C₁₂-TAC, (32) C₁₄-TAC (25-32, from Ref.^[79]). Black filled circles: neutral compounds or compounds exhibiting low charge (pK_a ≤ 8). Blue upward-pointing triangles: cationic compounds with intermediate charge (pK_a ≥ 8). Blue downward-pointing triangles: strongly charged cationic compounds (pK_a ≥ 9). (B): The free energy of binding per single cationic full charge, , and single HBA, as a function of the number of patterns per compound . Compound numbers and symbols as in (A), black open circles, uncharged compounds. The free energy per hydrogen bond (y-axis) decreases with the increasing number of hydrogen bonds in patterns per compound (x-axis). We extrapolated to one hydrogen bond in the case of electrically neutral compounds and compounds with low charge (red lines).