Kidneys and Metals Problem Set

Problem 5: Types of metal toxicity

For help to answer the question:

A.	enzyme inhibition
B.	carcinogenicity
C.	disruption of subcellular organelles
D.	corrosion

Tutorial

Many metals exert their toxic effects by interfering with enzymatic reactions in the body cells. Enzymatic reactions in the body are chemical reactions that are facilitated by special proteins called enzymes. For example, the "heme" group from hemoglobin is manufactured by a complex series of enzymatic reactions. Five of the enzymes involved in heme synthesis do not work very well at all in the presence of lead; that is, they are "inhibited" by lead. This can lead to anemia, a reduction in the number of red blood cells.

Disruption of subcellular organelles

Another type of damage often caused by metals occurs when they disrupt the function of organelles, such as the endoplasmic reticulum, lysozymes or mitochondria. This can happen when metals interfere with the enzymes in the organelle or sometimes by the presence of metal inclusion bodies. In the kidney tubules, mercury causes problems by interfering with the work of the cell membrane. Mercury binds to membrane proteins, disrupting their regular work of reabsorbtion of water and important solutes.

Carcinogenesis

Some metals can cause cancer. Arsenic, for example, has been linked to lung cancer and skin cancer. Scientists are not sure yet how metals cause cancer, but it may be because some metals somehow interact with DNA.

Corrosion

Lastly, because metals can be in several different charge states, they become easily involved with oxidation and reduction reaction and this can lead to corrosion or oxidative damage.