Measuring plasma enzymes activity is an important tool in diagnosis and monitoring of treatment.
Enzymes that have a physiological rol in blood, like coagulation enzymes, are present in plasma, but also can be found small quantities of enzymes that normally are present in tissues.
These quantities increase in some diseases of tissues and organs, since as a consequence of increased death cells or changes in cell membranes permeability, intracellular enzymes are released into plasma, giving clues about some organs diseases.
There is a strong association between the finding of an increase in plasma of particular enzymes, and the damage of organs that are rich in those enzymes.
A brief (and incomplete) list of enzymes that have been useful as diagnostic tools, and its main diagnostic uses include:
Enzymes and Related Diseases
Acid Phosphatase .- Some Prostatic diseases
Alanine aminotransferase (ALT). -Liver, Heart diseases
Aldolase .- Some muscle diseases
Alkaline Phosphatase.- Liver and Bone diseases
Amylase.- Pancreatic diseases
Angiotensin-Converting Enzyme (ACE) .- Active Sarcoidosis
Aspartate aminotransferase (AST).- Heart, Liver diseases
Cholinestarase (pseudocholinestarase).- Acute organophosphorus poisoning
Creatin Kinase (CK or CPK) .- Heart, Muscle diseases
Gamma-Glutamyltransferase (GGT).- Liver disease, alcohol rehabilitation
Lactate Dehydrogenase (LDH).- Heart, Liver, Brain diseases
Lysozyme.- Some acute leukemias
More general information about the use of enzymes in diagnostic can be found here.
As discussed previously, some enzymes that catalyze the same reaction, have different structure. They are called Isoenzymes or Isozymes. The diagnostic importance of the determination of the different isoenzymes of an enzyme, has been discussed in a former post.