Glutamic oxalacetic transaminase (GOT, aspartate aminotransferase EC 2.6.1.1) catalyzes reversibly the transamination of the amino, -NH2, group of L-aspartic acid to alpha-ketoglutaric acid with the subsequent formation of oxalacetic acid and L-glutamic acid, respectively. High concentrations of GOT are normally found in heart and liver tissues. After myocardial infarction, GOT activity is increased in the blood serum. The peak values of GOT are roughly proportional to the degree of cardiac tissue damage. Also, in case of liver diseases, such as hepatitis and jaundice, as well as muscular dystrophy and pulmonary emboli, an increased level of GOT activity in serum is observed. Accordingly, detection of the enzyme activity in blood serum is used for clinical diagnosis of myocardial infarction, hepatitis and other diseases. therefore, the availability of sensitive, accurate and reproducible methods for the assay of GOT activity is of prime clinical importance. This assay is done routinely in laboratories and hospitals for clinical diagnosis. This research proposes the development of new analytical methods in which both spectrophotometric and potentiometric techniques will be applied for the assay of GOT activity in flow- injection system for clinical purposes. L-aspartate produced during the more favorable GOT catalyzed reaction can be converted to ammonium and fumarate ions in the presence of L-aspartase. The ammonium ion, subsequently, can be detected spectrophotometrically and potentiometrically using ammonium ion selective electrodes. The concentration of ammonium ion is directly related to GOT activity. The application of two electrodes of the same kind; as reference and indicating electrodes; in flow system increases the sensitivity and minimizes interferences. The suggested methods are specific, accurate and sensitive. The proposed research also provides means and valuable information for kinetic studies of the GOT enzyme system.
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