Zinc Health

Zinc

Zinc

Zinc (English: zinc) is a chemical element, the chemical symbol is Zn, the atomic number is 30, the relative atomic mass is 65.39, is a transition metal; zinc is similar to lead because of its shape and color. Zinc is a hard and brittle substance at room temperature and has a blue-silver luster. Zinc is the first element in the twelfth group of the periodic table. In some ways, zinc has similar chemical properties to magnesium: both exhibit a single oxidation state (+2), and the Zn2 + and Mg2 + ions are similar in size. Zinc is the twenty-fourth element in the earth's crust and has five stable isotopes. The most common zinc-bearing ore is sphalerite, which is zinc sulfide. The largest mineable veins are located in Australia, Asia and the United States. Zinc minerals are refined by the froth flotation method, and are subjected to roasting and electro-refining.

This element may be named after the alchemist Paracelsus in German: Zinke (fork, tooth meaning). Pure metal zinc was discovered by German chemist Magruff in 1746. In 1800, Luigi Galvani and Alessandro Volta revealed the electrochemical properties of zinc. The main application of zinc is anti-corrosion iron galvanizing (hot-dip galvanizing), which has an indelible position in the manufacture of carbon-zinc batteries in modern industry. The most representative use is "galvanized iron sheet" Widely used in various industries such as automobiles, electricity, electronics and construction.

Zinc is an essential mineral, including prenatal growth and postnatal development [7]. About two billion people in developing countries are affected by zinc deficiency and its associated diseases [8]. If children lack zinc, it will lead to growth retardation, late sexual maturity, decreased immunity and diarrhea [7]. In biochemistry, zinc is a coenzyme widely present in enzymes, such as the alcohol dehydrogenase of the human body [9].

Excessive consumption of zinc may cause ataxia, depression, and copper deficiency.

Physical properties

Zinc is a bluish white, bright, and diamagnetic metal. Although zinc, which is generally used as a commodity, has been processed, these characteristics are no longer clear [10]. Its density is slightly smaller than that of iron, and it has a hexagonal crystal structure [11].

Zinc is hard and brittle at room temperature, but it becomes tough at 100 to 150 ° C [10]. When the temperature exceeds 210 ° C, zinc becomes brittle again, and it can be crushed by beating. [12] The conductivity of zinc is in the middle. Among all metals, its melting point (420 ° C) and boiling point (900 ° C) are relatively low [13]. Except for mercury and cadmium, its melting point is the lowest among all transition metals

Confirmation of the location of ZTL1 in human small intestinal cells

In the similar cells of intestinal cell Zn transport protein, it can be divided into two major categories, SLC30 and SLC39, of which two proteins hZTL1 (h; human) and hZIP4 play a very important role in the process of Zn uptake by intestinal cells. Before the discovery of ZTL1, no one saw Zn channels in mammalian cells.

ZnT1 was found on the cell membrane next to rat intestinal cells by immunoprecipitation, and was confirmed in human small intestine cells Caso-2.

ZIP1 was originally considered to be a transporter used to absorb Zn in the small intestine. The experiment of K562 cell membrane localization overturned this point. Green fluorescent and FLAG-labeled hZIP1 are located on the endoplasmic reticulum of many cortical cells, including Caco-2 In addition, it is possible to prove this more accurately by operating the hZIP1 antibody on PC-3 prostate cells.

 

Other possible Zinc transporter

Regarding other Zn transporters, there is a ZNT1 protein that plays a very important role in the intestinal tract. Studies have shown that ZNT1 will carry Zn ions obtained from the diet after absorption by intestinal parietal cells and into the hepatic portal vein, but there are no other proteins in the SLC30 protein. It was found to have exactly the same function as ZNT1.

In the human pancreatic islet cells, ZnT5 binds to an insulin-rich secretory granule, and Zn plays an important role in storing insulin in the form of crystals.

Although the two proteins ZNT6 and ZNT7 can be found in the intestine, their traces are found in other organs, so their functions are not similar to ZNT1.

In the human body, hZIP1, hZIP2, and hZIP4 all have the function of carrying Zn ions, but these proteins are also found in the uterus and prostate, so their functions are not completely clear. In addition, the functions of the two proteins, ZIP6 and ZIP8, are unknown. The same is true for ZIP7 found in rat endoplasmic reticulum.

Regulation of zinc channels in the small intestine and placenta

Regulation of zinc absorption in the small intestine is considered to be an important part of maintaining zinc balance in the body. In a rat study, it has been demonstrated that when the concentration of absorbable zinc increases, there is a position in the small intestine that will regulate the upstream mRNA of ZnT1 However, the same study also showed that when the absorbable zinc concentration decreased, the ZnT1 mRNA will not be affected, and the other zinc transfer protein ZnT2 will enhance the performance of ZnT2 mRNA when sufficient zinc is provided. In the case of ZnT2 mRNA expression will be reduced.