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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.
Calcium regulation in the human body. [6]The plasma ionized calcium concentration is regulated within narrow limits (1.3–1.5 mmol/L). This is achieved by both the parafollicular cells of the thyroid gland, and the parathyroid glands constantly sensing (i.e. measuring) the concentration of calcium ions in the blood flowing through them.
A calcium channel is an ion channel which shows selective permeability to calcium ions. It is sometimes synonymous with voltage-gated calcium channel, [1] which are a type of calcium channel regulated by changes in membrane potential. Some calcium channels are regulated by the binding of a ligand.
The U.S. Institute of Medicine (IOM) established Recommended Dietary Allowances (RDAs) for calcium in 1997 and updated those values in 2011. [6] See table. The European Food Safety Authority (EFSA) uses the term Population Reference Intake (PRIs) instead of RDAs and sets slightly different numbers: ages 4–10 800 mg, ages 11–17 1150 mg, ages 18–24 1000 mg, and >25 years 950 mg. [10]
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 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 ...
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. [1] [2] Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium silicate, [1] [3] which can deposit to form sediments or the ...
The structure of calcium pumps found in the sarcoplasmic reticulum of skeletal muscle was elucidated in 2000 by Toyoshima, et al. using microscopy of tubular crystals and 3D microcrystals. The pump has a molecular mass of 110,000 amu , shows three well separated cytoplasmic domains , with a transmembrane domain consisting of ten alpha helices ...