Zinc in biology
Most zinc is in the brain, muscle, bones, kidney, and liver, with the highest concentrations in the prostate and parts of the eye.[11] Semen is particularly rich in zinc, a key factor in prostate gland function and reproductive organ growth.[15][2] It interacts with "a wide range of organic ligands",[15] and has roles in the metabolism of RNA and DNA, signal transduction, and gene expression.[2][17][3] Dysregulation of zinc homeostasis in the central nervous system that results in excessive synaptic zinc concentrations is believed to induce neurotoxicity through mitochondrial oxidative stress (e.g., by disrupting certain enzymes involved in the electron transport chain, including complex I, complex III, and α-ketoglutarate dehydrogenase), the dysregulation of calcium homeostasis, glutamatergic neuronal excitotoxicity, and interference with intraneuronal signal transduction.[21] The metal also has a flexible coordination geometry, which allows proteins using it to rapidly shift conformations to perform biological reactions.[26] The non-related β-carbonic anhydrase is required in plants for leaf formation, the synthesis of indole acetic acid (auxin) and alcoholic fermentation.A coordinate covalent bond is formed between the terminal peptide and a C=O group attached to zinc, which gives the carbon a positive charge.This helps to create a hydrophobic pocket on the enzyme near the zinc, which attracts the non-polar part of the protein being digested.[38] The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for zinc in 2001.As for safety, the IOM sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient.[40] For U.S. food and dietary supplement labeling purposes, the amount in a serving is expressed as a percent of Daily Value (%DV).[45] For fortification, however, a 2003 review recommended cereals (containing zinc oxide) as a cheap, stable source that is as easily absorbed as the more expensive forms.[46] A 2005 study found that various compounds of zinc, including oxide and sulfate, did not show statistically significant differences in absorption when added as fortificants to maize tortillas.[49] Zinc supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth.[55] Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soy foods, nuts, peas, and seeds.[5] Zinc (Zn), alongside Magnesium (Mg) and Iron (Fe), constitutes one of the three families of biodegradable metals.
Zinc fingerstrace elementmicroorganismsenzymestranscription factorsmetallothioneinsaspartic acidglutamic acidcysteinehistidinetransition metalsprostate glandreproductive organligandssignal transductiongene expressionapoptosisin silicoArabidopsis thalianasynaptic vesiclesglutamatergicneuronssynaptic plasticityhomeostasiscentral nervous systemneurotoxicityelectron transport chaincomplex Icomplex IIIα-ketoglutarate dehydrogenaseexcitotoxicitySLC30A3Ribbon diagramcarbonic anhydraseLewis acidhydroxylationcoordination geometryconformationscarboxypeptidasecarbon dioxideindole acetic acidalcoholic fermentationcoordinate covalent bondhydrophobicZIP transportersDNA base sequencesamino acidsblood plasmaalbumintransferrinzinc signalingmetallothioneindopamine transporterhigh affinitybinding sitereuptakeamphetaminedopamine effluxin vitroserotonin transporternorepinephrine transporterEF-handcalcium binding proteinsU.S. Institute of MedicineTolerable upper intake levelsDietary Reference IntakesEuropean Food Safety AuthorityphytateReference Daily IntakeFoods and spicessesamealfalfacelerymustardalmondswhole grainspumpkin seedssunflower seedsblackcurrantfortified fooddietary supplementszinc oxidezinc carbonatezinc acetateZinc deficiencymalabsorptionacrodermatitis enteropathicaalopeciateratogenesisphytateschelatorcerealbiomarkerssensitivity and specificityCallunaVacciniumericoid mycorrhizal fungicultivatedzinc phosphidegalvanizedBibcodeUnited States Department of AgricultureGadd GMSodium in biologyMagnesium in biologyPotassium in biologyCalcium in biologyManganese in biologyIron in biologyCobalt in biologyCopper in biologySelenium in biologyMolybdenum in biologyIodine in biologyArsenic biochemistryBiological aspects of fluorineCHONPSCarbonHydrogenOxygenNitrogenPhosphorusSulfurDeficienciesChromiumCopper