In this article, we discuss different cation examples and their biological importance.
Anions are those species in which an atom or group of atoms contain a positive charge by releasing one or more than one electron. Mainly formed by metal atoms. In electrolysis, a cation attracted the cathode part of a cell.
A list of cations examples is given below.
- Calcium ion
- Ferrous / Ferric
- Zinc ion
- Manganese ion
- Nickel ion
- Molybdenum ion
- Cobalt ion
- Chromium ion
Sodium is an essential element in the human body.
Sodium is found predominantly in extracellular cation in the human body. With the help of the Na-K pump in the Na-K-ATPase Na+ ions participate in different biological interactions like transmission of nerve signals, maintaining osmotic pressure by Na gradient, and controlling the acid-base. The transport of carbohydrates, as well as amino acids, is regulated by the Na+ ion inside the cells. Glycogen synthesis is also regulated by the Na+ ion.
This cation is more efficient in the transport mechanism of a different enzyme. This is a important cation examples in bioinorganic chemistry.
Potassium ion (K+)
K+ ions are also as important as Na+ ions in the human body. It has a high concentration inside the cell, unlike sodium ions.
Potassium ion also participates in nerve signal along with sodium ion in NA-K ATPase. Even K+ is also activated by many enzymes and can participate in the oxidation of glucose to the formation of ATP. The concentration of Na+ is 10 mM, whereas the concentration of K+ is near about 105 mM, almost 10 times that of sodium ion in the blood cell of a human body. This is a important cation examples in bioinorganic chemistry.
Lithium-ion is not participating in any biological role but it can use as a cure for the diseases.
A mental illness called bipolar diseases is cured with the help of Li+ ion. It is more effective in the maniac phase of bipolar disorder. It promotes inhibitory neurotransmission and also interferes with the Na-k-ATPase. This is a important cation examples in bioinorganic chemistry.
Calcium ion (Ca2+)
Bone and teeth contain a major amount of Ca2+ ions than any other organ in the human body.
Calcium phosphate strengthens the teeth and bone where the Ca2+ ion is present. Osteoblasts synthesis and its secreting in the extracellular matrix of the bone also regulated by Ca2+. Ca2+ also plays a crucial role in clotting blood by promoting the enzyme thrombin and helping the cytoplasm of muscle fibers for muscle activity.
Ca2+ ions also help the endocrine system with three hormones, one of its vitamin D. This is an important cation examples in bioinorganic chemistry. This is a important cation examples in bioinorganic chemistry.
The less abundant element Mg2+ ion has homeostasis and the biological behavior similar to calcium.
Mg2+ is greatly involved in the photosystem of plants. Mg2+ maintains the rigidity structure of chlorophyll and minimizes the molecular vibration in the photosystem. Mg2+ ion enhances the rate of transformation of singlet to triplet state of photon absorption. Due to its strongly hydrated nature magnesium ion can bind with the ROPO3H group in nucleotides (ATP, ADP) and polynucleotides (DNA, RNA). This is an important cation examples in bioinorganic chemistry. This is a important cation examples in bioinorganic chemistry.
Ferrous (Fe2+) / Ferric (Fe3+)
The most important and crucial metal ion is ferrous and Ferric in metal-containing (heme) protein.
Ferrous ion is present at the active site of deoxyhemoglobin. Upon oxygen addition, the ferrous ion is oxidized to a Ferric ion and decreases its size to fit in the porphyrin cavity the form is called oxyhemoglobin. Ferrous and ferric ions have greater importance in the conversion of hemoglobin from the tense state to relax state.
Even Ferrous and ferric ion is present min different Fe-S proteins, e.g Rubradoxin,(1Fe, 0S), Ferredoxins (2Fe, 2S). these proteins have a greater role in electron transport in the human body.
Fe2+/Fe3+ is present at the active site in heme-containing protein cytochromes which is an important role to transfer electrons in biological reactions. The iron center is a redox-active center. These are an important cation examples in bioinorganic chemistry.
Cupric ion (Cu2+)
Cupric ion is an essential ion in human beings for several biological mechanism. Cu2+ is present at the active site in hemocyanin, which is an oxygen carrier protein in arthropods.
Cu2+ is present at the active site of different nonheme proteins e.g. cytochrome c oxidase which transfers an electron and tyrosinase which is oxygenase enzymes and superoxide dismutase.
Copper ions are absorbed and bind to albumin and transported to the liver and incorporated into ceruloplasmin which is transported to tissues. Even Cu2+ plays a crucial role in ferroxidase which is catalyzing the oxidation of Fe2+ to Fe3+ in a living system. These are an important cation examples in bioinorganic chemistry.
Zinc ion (Zn2+)
In the human body, almost 10% of proteins contain Zn. Zn is coordinated in many proteins like histidine (N-group), cysteine (S-group), glutamate (O-group), or aspartate (O-group) residues in protein structure of the human body.
The main role of Zn in proteins are structure stabilizing in CuZn -super oxidase dismutase in Zn finger, catalytic action in carboxypeptidase-A, enzyme, and regulating Zn transport proteins during signaling action.
Zn is also present in Carbonic Anhydrase which is a mettalozyme present in the membrane of the RBC and it catalyzes the carbon dioxide to bicarbonate at pH 7.4.
Carboxy peptidase A is an enzyme that can hydrolyze the peptide bond at the terminal carbonyl group present in the pancreas, the metal cofactor in the enzyme is Zn. This is a important cation examples in bioinorganic chemistry.
Manganese ion (Mn2+)
Manganese ion acts as a catalyst in the reaction for the oxygen-evolving complex.
The OEC (oxygen-evolving complex) is regulated for the oxidation of water molecules to dioxygen or superoxide in the photosystem II of the photosynthesis of plants. There is tetra manganese is present at the active site of that metalloenzyme (Mn4O5Ca). Mn superoxide dismutase acts as an antioxidant to neutralize the toxic effect of different reactive oxygen species like superoxide ions in the powerhouse of the cell.
Carbohydrates and fat metabolism are regulated by the Mn2+ ion in the human body. Manganese-containing cofactor enzymes take part in the formation of connective tissue, synovial fluid in the joints, and clotting of blood inside the muscle. This is an important cation examples in bioinorganic chemistry.
Nickel ion (Ni2+)
Nickel ion is the key metal for the gastric pathogen helicobacter pylori for human body.
Ni2+ ion has a greater role in the conversion of urea into carbon dioxide and ammonia at very low pH. Urease is Ni-containing metal enzyme which involves the conversion of urea into ammonia and carbon dioxide. This is an important cation examples in bioinorganic chemistry.
Molybdenum ion (Mo4+)
Molybdenum ion itself is inactive species in biological reaction but its complex by cofactor has a greater role in bioinorganic.
The main role of Mo enzymes is to catalyze the oxo group to its substrate. The oxidation state of Mo is changed from +4 to +6 during the transformation of the oxo group. Sulfite oxidase is Mo containing enzyme that catalyzed the degradation of sulfur-containing amino acids (e.g. cysteine).
Mo4+ is a cofactor of another metalloenzyme Xanthine dehydrogenase which involved the oxidation process of xanthine to uric acid which has an important role in nucleic acid metabolism. Another Enzyme aldehyde oxidase contains Mo4+ as a cofactor which plays an important role in the nitration fixation process. This is an important cation examples in bioinorganic chemistry.
Cobalt ion (Co2+)
Cobalt ion is the main cofactor and key component of the cobalamin enzyme (vitamin B12).
Cobalamin has two biologically active forms one is methylcobalamin and another is adenosylcobalamin and they are the cofactor for the methyltransferase of the B12 enzyme. In mammals’ body B12 dependent enzyme methionine aminopeptidase 2 (MetAP2) bind directly to the polypeptide and remove of N-terminal methionine from proteins. Co2+ has a greater role in the structure and proper activity of that enzyme. MetAP2 also plays important role in tissue repair and protein degradation. This is an important cation examples in bioinorganic chemistry.
Chromium ion (Cr3+)
Cr3+ is found in different foods and supplements and it has very low toxicity.
Cr ion is a part of an organic complex of glucose tolerance factors which is optimized for the effect of insulin. Cr ion also a functional part of oligopeptide of low molecular weights having substances glycine, cysteine, glutamic, and aspartic acid.
Cr6+ ion has greater importance in the medical aspect, it is uses anti-allergic skin medicine.