[5] This indicates that the transport of Cr3+ must involve an intermediate (i.e. chromodulin) and that Cr3+ is moved from the blood to tissues in response to increased levels of insulin.
[3][5] Subsequent protein isolations in rats, dogs, mice and cows have shown the presence of a similar substance, suggesting that it is found extensively in mammals.
[11] In addition, magnetic susceptibility studies have shown that chromium does not coordinate to any N-terminal amine groups but rather to carboxylates (although the exact the amino acids involved are still unknown).
[3] These magnetic susceptibility studies are consistent with the presence of a mononuclear Cr3+ center and an unsymmetric trinuclear Cr3+ assembly with bridging oxo ligands.
[11] No sulfur ligands coordinate to chromium and instead, it has been proposed that a disulfide linkage between 2 cysteine residues occurs owing to a characteristic peak at 260 nm.