Isozymes

2- What is the application of isozymes in clinical diagnosis? Give the names of some enzymes used in diagnostic kits.

Testing the serum content is a very useful tool in the clinical diagnosis in general. Normally the enzymes are present inside the cells and the enzyme activity in the serum is very low. As the tissue gets damaged, due to a disease or infection, enzymes can be released from the damaged cells into the serum. As enzymes are biological catalysts, the detection of the presence and the activity of them in the serum is relatively easy, comparing to other types of substrates, means those enzymes can serve as markers, as the concentration of them is increased in the serum indicating tissue damage. For example, amylase detected in the serum is a marker for damaged pancreas tissue. The problem arises when the enzyme detected in the serum is present in more than one type of tissue throughout the body. One common example is phosphatase, which can be found throughout the human body, and concentrated in tissue such as RBC, the bones, the liver and kidney, which makes it difficult to know the
Isozymes can be found also in the same tissue but in different organisms. Isozymes have different gene determination, due to gene duplication or ancestral mutation event, means that they have chemical, physical or even immunological differences in their properties, such different optimum temperature, different optimum pH value, different Km and Vmax values, different substrate affinity, differences in the secondary and tertiary structure, and different reactivity with specific antibodies. Due to these differences, isozymes can be separated from each other, through a wide range of techniques, and the most applied techniques are electrophoresis and