Optimal Assay Conditions for Serum and Liver Glutamate Oxaloacetate Transaminase, Glutamate Pyruvate Transaminase, and Sorbitol Dehydrogenase from the Rainbow Trout, Salmo gairdneri

Abstract

A technique often used to minitor sublethal impairment of physiological functions in fish is clinical serum enzyme analysis. However, the assay conditions used in such studies in fish systems are often those derived from mammalian studies. For some enzymes (e.g. sorbitol dehydrogenase) mammalian assay conditions are applicable to fish serum; however, for glutamate oxaloacetate transaminase and glutamate pyruvate transaminase, assay conditions must be modified for fish systems. This paper thus reports pH and substrate optima for rainbow trout SDH, GOT, and GPT. Using these optimal assay conditions, liver GOT, GPT, and SDH activities were determined to be 187, 152, and 26.6 mU/mg protein, respectively. The equivalent serum GOT, GPT, and SDH activities were 255, 17, and 17.5 mU/mL serum, respectively.Key words: rainbow trout, serum enzyme analysis, glutamate dehydrogenase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, sorbitol dehydrogenase, liver, biochemistry