Proton magnetic resonance studies of methionine enkephalin.
In the literature there exist two conflicting pieces of data concerning the thermodynamics of the Cu(2+)-methionine enkephalin complex. One study utilized 1H nuclear magnetic resonance (NMR) to study the solution phase Cu(2+)-enkephalin binding and reported a strong interaction over a wide pH range. Another study utilized potentiometry to measure a log beta 101 of 4.6, a value representative of a weak metal-ligand complex. In order to resolve this discrepancy a 300 MHz 1H NMR is used to study the protonation sequence of methionine enkaphalin, a bioactive peptide, and its complexation with seven diamagnetic metals (Ba2+, Ca2+, Zn2+, La2+, Mg2+, Sr2+ and Cd2+).
Manning
T J
TJ
Department of Chemistry, Valdosta State University, Georgia 31698, USA.
Tonui
P
P
Miller
A
A
Toporek
S
S
Powell
D
D
D019342:Acetic Acid; D001665:Binding Sites; D002413:Cations, Divalent; D003300:Copper; D004744:Enkephalin, Methionine / Q000737:chemistry*; D005030:Ethylenes; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011487:Protein Conformation; D013816:Thermodynamics
D002413:Cations, Divalent; D005030:Ethylenes; D008024:Ligands; D004744:Enkephalin, Methionine; D003300:Copper; C036216:ethylene; D019342:Acetic Acid