Table 3

Inhibition of TSP-1 binding to CD36 by Mal II peptides

PeptideIC50
Cell bindingSolid phase
nM
Unmodified Mal II>10,0001,000
d-Ser5-Mal II, 19-mer6.22  ± 5.027.4  ± 4.2
d-IIe15 Mal II variants
 Original 19-mer20.8  ± 12.312.5  ± 3.3
 Nonapeptide15.4  ± 8.912.8  ± 4.2
 Ethylamide-capped heptapeptide6.8  ± 4.14.6  ± 3.3
 Retro-inverso11.2  ± 5.828.4  ± 5.4
  • Binding of 125I-labeled TSP-1 (20 μg/ml) to a confluent monolayer of Bowes melanoma cells expressing CD36 or to solid-phase fusion protein expressing CD36 amino acids 93 to 155 immobilized on plastic was competed with increasing concentrations of hyperpurified inactive Mal II or various Mal II analogs. IC50 values were determined using the ENZFITTER curve-fitting program.