Complexes of W(VI) and Mo(VI) with glycolic, lactic, chloro- and phenyl-lactic, mandelic, and glyceric acids studied by 1H and 13C nuclear magnetic resonance spectroscopy

1987 ◽  
Vol 65 (4) ◽  
pp. 827-832 ◽  
Author(s):  
M. Madalena Caldeira ◽  
M. Luisa Ramos ◽  
Victor M. S. Gil
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Magnetic Resonance Study ◽  
Ph Values ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

A proton and carbon-13 nuclear magnetic resonance study is reported on the number, stoichiometry, geometry, and stability of the complexes that form when sodium tungstate or sodium molybdate is mixed with each one of the following α-hydroxyacids in aqueous solution at pH values in the range 3–8: glycolic, lactic, chloro-3- andphenyl-3-lactic, mandelic, and glyceric acids. The predominant complexes have 1:2 composition and pK of formation of the order of −5 to −16.

A Nuclear Magnetic Resonance Study of the Metal Binding Sites in Bacitracin

1975 ◽  
Vol 53 (12) ◽  
pp. 1250-1254 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Moira R. Graham
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Metal Binding ◽  
Binding Sites ◽  
Imidazole Ring ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Metal Binding Sites ◽  
Ph Values ◽  
Nuclear Magnetic

Carbon-13 nuclear magnetic resonance spectroscopy has been used to identify sites in bacitracin which bind Cu2+ and Mn2+. Results are presented which implicate the free carboxyl groups of the aspartic and glutamic acid residues and the imidazole ring of the histidine residue as metal complexation sites between pH 6 and 8. Evidence is presented which also indicates that the thiazoline ring of bacitracin binds Mn2+. Bacitracin does not bind Cu2+ or Mn2+ at pH values of 2.5 or less.

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