Paper Example on Isoenzymes of Lactate Dehydrogenase

Introduction

Isoenzymes are multiple types of enzymes which are different in physical and structural composition and properties; but accelerate the same chemical reactions at different rates (Epstein, 2017). LDH enzymes are found in both plants and animals. LDH enzymes are present in many body tissues such as the heart, red blood cells, liver, kidneys, brain, and other tissues (Epstein, 2017). There are five forms of LDH with different structures and concentration. For example, LDH-1 is found in red blood cells and heart muscle while a high concentration of LDH-3 is found in lungs.

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Use of Isoenzymes of LDH as Diagnostic Tools

Isoenzymes of LDH test can be used as a diagnostic tool to establish its content in the human blood. The test is administered on patients suspected to have had a heart attack, blood disorder, or damaged tissue or damaged liver (Epstein, 2017). That is, spillage of LDH isoenzymes in the blood is an indication of tissue damage. The test for isoenzymes of LDH varies based on age, gender, health history, and test method applied. Under normal circumstances, the test ratio should give a value where LDH-1 is less than LDH-2 while LDH-5 should be less than LDH-4 (Epstein, 2017). Therefore, a greater LDH-1 than LDH-2 will indicate that a patient has had a heart attack in the past one week. On the other hand, greater LDH-5 than LDH-4 will indicate that a patient has a damaged liver or liver disease. However, a patient who suffers from two diseases associated with a rise in more than one LDH will not be diagnosed for the two diseases because one disease will definitely hide the other.

One Other Diagnostic Test Not Using LDH Isoenzymes

One other diagnostic test which can be used to determine damage or injury to the muscle tissue, heart, or brain is creatine phosphokinase test (CPK). CPK is an enzyme found in the heart, brain, and skeletal muscle (Pietrangelo, 2017). A blood sample can be tested to determine the amount of CPK in the blood. Whenever the tissue is damaged or injured, the CPK will leak into the bloodstream. Therefore, CPK test will help establish the exact tissue which has been damaged. The normal value for CPK in the blood should be 10-120 mcg/L. However, high levels of CPK-1 will indicate brain injury, seizure, brain cancer, or dead lung tissue. Similarly, high levels of CPK-2 will indicate heart injury, heart tissue inflammation, electrical injury, or heart attack (Pietrangelo, 2017). High levels of CPK-3 will indicate damaged muscles, immobile tissue muscle, inflamed muscle, or damaged muscle.

Advantages and Disadvantages Exist Over Using LDH Isoenzymes

CPK test is more specific to body tissue thus might offer great insight into the damaged tissue compared to LDH tests. For example, CPK-1, CPK-2, and CPK-3 are specific to the brain and lungs, heart, and skeletal muscle respectively (Pietrangelo, 2017). CPK is only affected by cardiac catheterization, intramuscular injections, muscle trauma, latest surgery, and heavy exercise, unlike LDH test which is susceptible to medications and drugs such as vitamin C, aspirin, and narcotics among others (Pietrangelo, 2017). Specificity of CPK test makes it suitable for use in non-clinical safety studies as opposed to LDH which lacks specificity. Disadvantages associated with the CPK test include the fact that it is less sensitive compared to the LDH test when used to diagnose the extent of the area of necrosis.

References

Epstein, J. (2017). Lactate dehydrogenase test. Retrieved 29 November, 2018 from https://www.healthline.com/health/lactate-dehydrogenase-test

Essay Biology Class. (2018). Classification of proteins based on structure and function. Retrieved 29 November 2018, from https://www.easybiologyclass.com/classification-of-proteins-based-on-structure-and-function/

Pietrangelo, A. (2017). CPK isoemzymes test. Retrieved 29 November 2018, from https://www.healthline.com/health/cpk-isoenzymes-test