代谢
锌可以通过肺部、皮肤和胃肠系统进入人体。肠道对锌的吸收是由锌载体蛋白CRIP控制的。锌还与金属硫蛋白结合，帮助防止过量锌的吸收。锌在体内广泛分布，存在于所有组织和组织液中，尤其在肝脏、胃肠系统、肾脏、皮肤、肺、大脑、心脏和胰腺中含量较高。在血液中，锌与红细胞中的碳酸酐酶结合，也与血浆中的白蛋白、α2-巨球蛋白和氨基酸结合。白蛋白和氨基酸结合的锌可以扩散穿过组织膜。锌通过尿液和粪便排出体外。砷主要通过吸入或摄入吸收，皮肤接触吸收较少。砷在体内分布广泛，如果需要，它会被还原成亚砷酸盐，然后通过亚砷酸盐甲基转移酶甲基化成单甲基砷(MMA)和二甲砷酸(DMA)。砷及其代谢物主要通过尿液排出体外。砷已知能诱导金属结合蛋白金属硫蛋白，金属硫蛋白通过结合砷和其他金属，使它们生物活性失效，并作为抗氧化剂，从而减少砷和其他金属的有毒效果。
Zinc can enter the body through the lungs, skin, and gastrointestinal tract. Intestinal absorption of zinc is controlled by zinc carrier protein CRIP. Zinc also binds to metallothioneins, which help prevent absorption of excess zinc. Zinc is widely distributed and found in all tissues and tissues fluids, concentrating in the liver, gastrointestinal tract, kidney, skin, lung, brain, heart, and pancreas. In the bloodstream zinc is found bound to carbonic anhydrase in erythrocytes, as well as bound to albumin, _2-macroglobulin, and amino acids in the the plasma. Albumin and amino acid bound zinc can diffuse across tissue membranes. Zinc is excreted in the urine and faeces. Arsenic is absorbed mainly by inhalation or ingestion, as to a lesser extent, dermal exposure. It is then distributed throughout the body, where it is reduced into arsenite if necessary, then methylated into monomethylarsenic (MMA) and dimethylarsenic acid (DMA) by arsenite methyltransferase. Arsenic and its metabolites are primarily excreted in the urine. Arsenic is known to induce the metal-binding protein metallothionein, which decreases the toxic effects of arsenic and other metals by binding them and making them biologically inactive, as well as acting as an antioxidant. (L20, L49)
来源:Toxin and Toxin Target Database (T3DB)
