Isoenzymes Information and Courses from MediaLab, Inc.

In the past, an AMI was primarily diagnosed by evaluating symptoms at patient presentation, ECG measurement, and results of enzyme assays that were considered cardiac enzymes. The enzymes, creatine kinase (CK), lactate dehydrogenase (LD), and aspartate aminotransferase (AST) were assayed several times a day often for several days to observe peak concentration and return to normal level for each enzyme. The first assay result was the baseline level or baseline concentration. Isoenzymes of CK and LD were later added for AMI diagnosis. All three of these enzymes are found in other tissues, making the diagnosis difficult and lengthy. In the 1980s, CK isoenzyme, CK-MB, though not totally cardiac specific, became the benchmark marker for an AMI. None of these enzymes are in any of the current recommendations except for CK-MBCurrent diagnosis, monitoring, and screening relating to heart disease includes measurement of lipids, proteins, enzymes, and other biomolecules. Risk stratification for cardiac and vascular disease is an additional role for measurement of these analytes. The physiological changes in the development of heart disease are better understood and the role of the clinical laboratory is greatly expanded.Today's markers are significant because of their location in the myocyte, the kinetics of their release in myocyte damage, and their rate of clearance from peripheral blood.

Agarose gels are chemically purified forms of agar, a polysaccharide extracted from seaweed. The gel pores allow for separation of proteins based on their individual charge and mass. Agarose gel will naturally clear after drying the separated proteins.Common clinical uses of agarose gel electrophoresis (AGE) are separations of plasma proteins, hemoglobin variants, lipoproteins, and isoenzymes. The gels come prepackaged with a plastic template to lay over gel for sample application or slots etched in the gel for these samples.

IEF's greatest advantage is its high resolution, resulting in greater separation of solutes. IEF of serum proteins results in many more bands; these bands are sharper because each pH region is very narrow. Performing IEF is easier because the placement of sample application is not important. The sample and ampholytes can be mixed before application; the ampholytes will migrate, create the gradient, and then the proteins separate and migrate.Some isoenzymes and variant hemoglobins in prenatal screening are separated with IEF. Detection of oligoclonal bands in gamma-globulin is a newer use of IEF. IEF is commonly used as one of the separations in two-dimensional electrophoresis.