AT4 receptor binding characteristics: d-Amino acid- and glycine-substituted peptides

Abstract

The ability of angiotensin IV (AIV) analogs to compete for [125I]AIV binding in heat-treated bovine adrenal membranes was examined. Angiotensin IV displayed a Ki of 2.63 ± 0.12 nM. Peptides containing mono-substitutions with glycine or the corresponding d-amino acid in positions one, two, or three possessed Kis greater than 100 nM. Conversely, substitutions at positions four, five, and six produced peptides with Kis less than 8 nM. These data suggest that the N-terminal domains of the AIV peptide are critical for receptor binding, while the C-terminal domains play a less decisive role in receptor specificity. © 1993.