Asparaginase and Asparagine Transaminase in Soybean Leaves and Root Nodules 1

AUTOR(ES)

Streeter, John G.

RESUMO

Asparaginase activity (≤1 μmol/mg protein · hr) was detected in extracts of soybean (Glycine max [L.] Merr.) leaf blades, but, even after efforts to optimize extraction and assay of the enzyme, specific activity was not sufficient to metabolize the estimated amount of asparagine translocated to leaves. Asparagine transaminase activity with glyoxylate or pyruvate was at least 52 and 62 nmol/mg protein · hr, respectively. This estimate of transaminase activity is based on the analysis of the reaction product α-ketosuccinamate. Formation of glycine and alanine was confirmed by amino acid analysis. α-Ketosuccinamate deamidase had a specific activity of 85 nmol/mg protein · hr in leaf blade extracts.

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