Trace elements Lec 17 In biochemistry a trace

Trace elements Lec. 17

In biochemistry, a trace element is a chemical element that is needed in minute quantities for the proper growth, development, and physiology of the organism. In biochemistry, a trace element is also referred to as a micronutrient. n In the body an average concentration of less than 100 parts per million atoms, or less than 100 micrograms per gram. n

Trace Element Deficiency The common trace element is that in: n Iron during reproductive years. n Iodine causes goitre, hypothyroidism. n Measurements are often in plasma

Zinc It is essential for the activity of many enzymes and protein synthesis. n Its deficiency include dermatitis and delayed wound healing. n Patient following trauma or major surgery lose large amount of zinc in the urine and may depleted. n Sever deficiency in which an inherited defect in intestinal zinc absorption. n

In plasma zinc conc. blood should be colected in the fasting state since Zn conc. Fall up to 20% following a meal. n Low plasma conc. are not special to Zn deficiency. n Plasma Zn conc. fall during an acute phase response as a result of uptake by the liver. n As Zn is bound to albumin, plasma Zn conc. should be considered in relation to that of albumin. n

Copper n n It is essential for the activity of certain enzymes (cytocrome oxidase and superoxide dismutase). In blood 80 -90% of Cu is present in caeruloplasmin. Copper deficiency manifestation include anaemia and leucopenia. Wilson’s disease. It is a rare inherited disorder in which excessive amounts of copper accumulate in the body. The buildup of copper leads to damage in the kidneys, brain, and eyes.

Selenium is required as a prosthetic group for the enzyme glutathione peroxidase. n Selenium together with the tocopherols (vit E) is part of antioxidant system. n These highly reactive species can be generated (as a result of phagocytotic cells or exposure to ionizing radiation). n Selenium deficiency is usually only due to low intake. n

The most clinical feature is myopathy (cardiomyopathy). n Selenium can be measured in plasma but better to measure red cell glutathione peroxidase activity. n It is toxic in large amounts. n trace amounts of it, forming the active center of certain enzymes, are necessary for the function of all cells. n