Magnesium ions transport

FIGURE 8. Current model for the gating mechanism in the CorA transporter. Left closed conformation with the magnesium binding sites in the sensor occupied. Right postulated open conformation allowing ion transport into the ceU. Adapted by permission of MacmiUan Publishers Ltd. from Reference 71... 

The uptake of Mn2+ or Co2+ by system I is inhibitory or lethal respectively, and leads to efflux of Mg2+ from the cell. It is likely that accumulated Mn3+ or Co2+ displaces Mg2+ from ribosomes, thus increasing intracellular free magnesium ions, which leave the cell via the Mg2+ transport systems. 

Magnesium is an activator of more enzymes than any other element. It is an essential constituent of chlorophyll where about 2.7% of the weight of the chlorophyll molecule is magnesium. It is also involved in ion transport and cation balance in... 

Transport of magnesium ion across the inner membrane is not considered. Therefore the Mg2+ ion kinetics is governed by binding and unbinding to biochemical... 

Wodzki R and Klosinski P. Magnesium and calcium ions transport by synthetic analogs of teichoic acids with 1,2- and 1,3-hnked phosphodiester units. Makromol Chem, 1990 191(4) 921-931. 

The question for the nutritionist and clinician is Which Mg-dependent function is most sensitive to depletion of the body s magnesium and to hypomagnesemia The answer is probably ion transport systems, such as the calcium pump and Np,K-ATPase. The impaired activity of these ion pumps is likely to be responsible for the neuromuscular problems that present with an Mg deficiency. The defects would involve a difficulty in maintaining the normal movements of calcium, sodium, and potassium ions required for nerve conduction and muscle contraction,... 

Principle The EDTA-plasma sample is applied onto the protective mesh. Integrated precipitation and lipoprotein fractionation by means of dextrane sulfate and magnesium ions then take place in the precipitation layer. The precipitated lipoprotein fractions - chylomicrones, VLDL (very low density lipoproteins) and LDL (low density lipoproteins) - are filtered by the transport layer and only the HDL (high-density lipoproteins) fraction reaches the indicator him where the HDL cholesterol concentration is determined enzymatically by the following reaction ... 

As a consequence of the blockade of the Na, K, 2Cr-cotransporter, the diuresis produced by furosemide (frusemide) results in increased urinary excretion of sodium, potassium, chloride, calcium and magnesium ions. The losses of sodium, potassium and chloride are approximately 1750, 600 and 2150 mmol, respectively, after i.m. administration of furosemide (frusemide) at 1 mg/kg. Although these electrolyte losses are substantial, they are largely replaced (within the 24 h period following furosemide (frusemide) administration) by enhanced renal reabsorption as well increased ion absorption from the intestinal tract. In addition to this primary action, furosemide (frusemide) may have a lesser inhibitory effect on other chloride ion transporters and the drug can also inhibit carbonic anhydrase activity (Martinez-Maldonado Cordova 1990, Rose 1989,1991, Wilcox 1991). Finally, some of the renal and extrarenal effects of furosemide (frusemide) appear to be mediated through increased prostaglandin production. 

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