TY - JOUR
T1 - A fluorescence study of the binding of calcium and terbium ions to angiotensin
AU - Lenkinski, Robert E.
AU - Glickson, Jerry D.
AU - Walter, Roderich
N1 - Funding Information:
This work was supported by USPHS Grant AM-18399 (RW) and CA-13148 (JDG). Address correspondence to Dr. Robert E. Lenkinski Comprehensive Cancer Center, University of Alabama in Birmingham, Birmingham. Alabama 35294.
PY - 1978
Y1 - 1978
N2 - The interactions of angiotensin II and a synthetic analogue, [Asn1, Val5] angiotensin II, with Ca2+ and Tb3+ have been monitored using the intrinsic fluorescence of the tyrosine residue at position 4 in both molecules. The data indicate that angiotensin II binds both metals with a dissociation constant of ∼1 × 10-4 M-1, while no significant binding was observed with the amide analogue. This suggests that the side chain carboxyl group of aspartic acid forms part of the binding site. Since the value of the dissociation constant suggests chelation of the metals by the hormone, the terminal carboxyl group of the peptide is also probably involved in metal binding. The fact that energy transfer was observed between Tb3+ and the tyrosine of angiotensin places the hydroxl or carbonyl group of the tyrosine close to the metal binding site.
AB - The interactions of angiotensin II and a synthetic analogue, [Asn1, Val5] angiotensin II, with Ca2+ and Tb3+ have been monitored using the intrinsic fluorescence of the tyrosine residue at position 4 in both molecules. The data indicate that angiotensin II binds both metals with a dissociation constant of ∼1 × 10-4 M-1, while no significant binding was observed with the amide analogue. This suggests that the side chain carboxyl group of aspartic acid forms part of the binding site. Since the value of the dissociation constant suggests chelation of the metals by the hormone, the terminal carboxyl group of the peptide is also probably involved in metal binding. The fact that energy transfer was observed between Tb3+ and the tyrosine of angiotensin places the hydroxl or carbonyl group of the tyrosine close to the metal binding site.
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U2 - 10.1016/S0006-3061(00)80169-6
DO - 10.1016/S0006-3061(00)80169-6
M3 - Article
C2 - 647063
AN - SCOPUS:0017873607
SN - 0006-3061
VL - 8
SP - 363
EP - 368
JO - Bioinorganic Chemistry
JF - Bioinorganic Chemistry
IS - 4
ER -