Metalloproteins

A protein that has a metal ion cofactor is referred to as a "metalloprotein" in general. This group includes a sizable fraction of all proteins. For instance, although there may be up to 3000 human zinc metalloproteins, at least 1000 human proteins have zinc-binding protein domains. A metal is thought to be present in around half of all proteins. According to another estimate, between 25 and 30 percent of all proteins are thought to need metals in order to function. As a result, metalloproteins serve a variety of purposes in cells, including the storage and movement of proteins, the transportation of enzymes and signalling proteins, and the prevention of infectious illnesses. The prevalence of metal-binding proteins might be a natural consequence of the amino acids that proteins employ, as even synthetic proteins devoid of evolutionary history will readily bind metals. The majority of metals in the human body are linked to proteins. For instance, hemoglobin's iron content accounts for the majority of the body's relatively high iron concentration. Metal ions in metalloproteins are typically coordinated by nitrogen, oxygen, or sulphur centres located in the protein's amino acid residues. The side-chains on the amino acid residues frequently serve as these donor groups. The carboxylate groups that aspartate provides, the thiolate substituents in cysteine residues, and the imidazole substitutes in histidine residues are all particularly significant. Almost all amino acid residues have been demonstrated to bind metal centers, which is not surprising given the diversity of the metalloproteome. Deprotonated amides and amide carbonyl oxygen centres are two additional donor groups that are provided by the peptide backbone.