I have a question that came up in my research (neurobiology), maybe someone can help me out! I read that neuromelanin, which is found in certain brain structures, can chelate iron and protect cells from the toxicity of iron. I also read that chelation means "incorporation of a mineral ion or cation into a complex ring structure" and I know chelation is used to remove iron e.g. in case of overload. However what I don't understand is if chelation will "degrade" the iron molecule (I'm not familiar with the right terminology, sorry!) or if it will just "contain" it but the iron is still intact. The reason why I'm asking is because there is this notion of iron influencing MRI signal in certain regions that contain neuromelanin which binds/chelates iron, but at the same time chelation seems to mean removal. So I'm wondering if chelated iron still has the same properties as "free" iron. Thank you in advance!
"Neuromelanin pigment is able to accumulate different metals, mainly iron. Neuromelanin seems to be the most effective system for scavenging iron, which results in a long-term immobilisation of iron inside neurons." (Ward et al., 2014, The role of iron in brain ageing and neurodegenerative disorders)
"Low Iron in LC Neurons Is Chelated by NM. NM is a strong chelator of heavy metals because of the presence of catechol groups in its structure (31). NM has strong chelating ability for iron, which provides another important mechanism of protection from iron mobilization and the consequent toxicity." (Zecca et al., 2004, The role of iron and copper molecules in the neuronal vulnerability of locus coeruleus and substantia nigra during aging)