Distribution of Transaminases (Aminotransferases) in the Tissues of Pacific Salmon (Oncorhynchus), with Emphasis on the Properties and Diagnostic Use of Glutamic-Oxalacetic Transaminase

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Abstract
A partially purified glutamic-oxalacetic transaminase (GOT) from salmon liver was shown likely to function best at a pH > 7.5, to be specific for the L isomer of aspartic acid, and to require pyridoxal phosphate for activity. The coenzyme appeared to be tightly bound to the apoenzyme. A survey of the scope of apparent transaminations in dialyzed homogenates of brain, heart, kidney, liver, and muscle indicated that GOT and glutamic-pyruvic transaminase were active in all tissues and that cr-ketoglutarate (PHYSIOLOGICAL STUDIES-KG) was a more widely used amino acceptor than pyruvate. No transamination to the amino acceptors [alpha]-KG or pyruvate could be detected using as donors [beta]-alanine, D-alanine, gamma-aminobutyrate, glycine, histidine, proline, serine, or threonine. The following amino acids showed various degrees of transamination with [alpha]-KG in at least some tissue homogenates L-leucine, L-norvaline, L-ornithine, L-phenylalanine, L-tyrosine, and L-valine. Interpretation of these results is discussed, particularly in relation to comparative biochemistry. Spectrophotometric estimations of plasma or serum GOT levels were used to distinguish at a significant level (p < 0.01), apparently healthy fish from those treated with the hepatic poisons bromobenzene and CCl4 or those affected by bacterial kidney disease. The practical value of using GOT estimations as a diagnostic tool is discussed. It is tentatively suggested from limited data that the activity (units of enzyme/milligram tissue N) of GOT in various tissues decreases in the following order: heart, liver, kidney, and muscle.