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Calcium is readily complexed by oxygen chelates such as EDTA and polyphosphates, which are useful in analytic chemistry and removing calcium ions from hard water. In the absence of steric hindrance , smaller group 2 cations tend to form stronger complexes, but when large polydentate macrocycles are involved the trend is reversed.
The most striking use of Ca 2+ ions as a structural element in algae occurs in the marine coccolithophores, which use Ca 2+ to form the calcium carbonate plates, with which they are covered. Calcium is needed to form the pectin in the middle lamella of newly formed cells. Calcium is needed to stabilize the permeability of cell membranes.
Phosphates form insoluble salts in combination with calcium ions. High concentrations of HPO 4 2− in the plasma, therefore, lower the ionized calcium level in the extra-cellular fluids. Thus, the excretion of more phosphate than calcium ions in the urine raises the plasma ionized calcium level, even though the total calcium concentration ...
Since it transports Ca 2+ into the extracellular space, the PMCA is also an important regulator of the calcium concentration in the extracellular space. [4] PMCAs belong to the family of P-type primary ion transport ATPases which form aspartyl phosphate intermediates. [2] Various forms of PMCA are expressed in different tissues, including the ...
The concentration of calcium (Ca 2+ ions) is normally several thousand times higher outside the cell than inside. Activation of particular VGCCs allows a Ca 2+ influx into the cell, which, depending on the cell type, results in activation of calcium-sensitive potassium channels , muscular contraction , [ 4 ] excitation of neurons, up-regulation ...
Calcium signaling is the use of calcium ions (Ca 2+) to communicate and drive intracellular processes often as a step in signal transduction. Ca 2+ is important for cellular signalling , for once it enters the cytosol of the cytoplasm it exerts allosteric regulatory effects on many enzymes and proteins .
The α 1 subunit of T-type calcium channels is similar in structure to the α subunits of K + (potassium ion) channels, Na + (sodium ion) channels, and other Ca 2+ (calcium ion) channels. The α 1 subunit is composed of four domains (I-IV), with each domain containing 6 transmembrane segments (S1-S6). The hydrophobic loops between the S5 and S6 ...
The SR contains ion channel pumps, within its membrane that are responsible for pumping Ca 2+ into the SR. As the calcium ion concentration within the SR is higher than in the rest of the cell, the calcium ions will not freely flow into the SR, and therefore pumps are required, that use energy, which they gain from a molecule called adenosine triphosphate (ATP).