Differences of cytoplasmic transaminase activity in normal and opaque-2 maize (Zea mays L.) seedlings

The activity of glutamate-oxalacetate and glutamate-pyruvate transaminases (GOT 2.6.1.1., GPT 2.6.1.2.) was determined in seedlings of normal and opaque-2 maize. The activity of these transaminases was determined in homozygotes +/+ and o2/o2, their F1 hybrid, in mixture of +/+ and +/o2 in S3F4 generation. The GOT and GPT activity in mutants opaque-2 was always higher than in normal plants. In generation S3F4 the higher activity of transaminases in opaque-2 plants was demonstrated without addition of the pyridoxal-5-phosphate (PRP) coenzyme (at GOT 1,36x, at GPT 2,00x) as well as at the optimum PRP concentration (at GOT 1,39x, at GPT 2, 48x). The difference in transaminase activity is therefore not due to changes in PRP biosynthesis.The determination of the GOT and GPT activity in seedlings might be used in breeding experiments as a screening method for selection of mutants.