INTRAMOLECULAR ENERGY TRANSFER IN ADRENOCORTICOTROPIN

The efficiencies for singlet energy transfer for the Tyr-2 and Tyr-23 residues to the Trp-9 residue were measured by excitation spectroscopy. Using Förster’s theory for longrange energy transfer the intramolecular distance between residues 2 and 9 is estimated to be 10 A and that between residues 9 and 23 is estimated to be 19 Å or more, the experimental uncertainties being about 15%. The emission spectrum of adrenocorticotropin shows that Trp-9 is well hydrated. The experimental methods are applicable to several peptide hormones and small proteins. © 1969, American Chemical Society. All rights reserved.