Copper glycinate structure

Recently similar doublet structures have been observed in other systems with inversion symmetry58,66). Fujimoto et al.58) used a somewhat different perturbation approach for the explanation of the 14N-ENDOR spectra in copper-doped a-glycine, whereas Brown and Hoffman66) determined the nitrogen ENDOR frequencies of Cu(TPP) and Ag(TPP) by numerical diagonalization of the spin Hamiltonian matrix for an electron interacting with a single pair of equivalent 14N nuclei. 

In the chelates of glycine, aspartic acid, and glutamic acid all the carbon and nitrogen atoms form part of the ring structure. This probably is the reason why these three acids appear to outlast all others in high rank coal. It should be pointed out that in the presence of hydrogen sulfide, copper is precipitated as the sulfide from copper-amino acid chelates. Thus, copper and perhaps other elements could be transported as amino acid chelates until sufficient hydrogen sulfide was encountered to cause precipitation. 

Several biologically active peptides have a C-terminal a-amide structure that is formed by the action of a copper- and ascorbate-dependent monoxygenase on a C-terminal glycine. 

INNER COORDINATION COMPOUNDS A particular type of non-localized bond occurs in the so-called inner coordination compounds. This group of compounds may be illustrated by reference to the copper salt of aminoacetic acid (glycine). This compound dissociates only weakly in solution, it possesses a colour similar to the ammino complexes of copper and does not react with ammonia. These properties all tend to show that copper atom has a saturated valency and may be explained by considering the copper as bound to both the hydroxyl and the amino groups. In accordance with our concept of the nature of the bond between a metal and an amino group in such a compound, the structure of the complex will be represented by resonance amongst the forms I to IX X... 

Copper is often found in biochemical systems, usually in peptides and proteins. Extensive reviews may be found (66, 106, 557). Semiquantita-tive discussion (112) of the significance of the results, which usually show that the copper environment has axial symmetry and with a distorted octahedral structure are numerous. The use of model compounds has been discussed by Malmstrom and Vanngard (477). In many cases there appears to be dimeric species present (9S). A system of importance which has been extensively studied is the series of complexes with glycine and triglycine (209, 638, 707, 712). The ESR data are tabulated in Table LV. 

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