Purification, properties and formation of arginine-alpha-ketoglutarate transaminase in Arthrobacter simplex

Arginine-alpha-ketoglutarate transaminase was purified 460-fold with 1.4% yield from Arthrobacter simplex grown on arginine as a carbon source. The preparation was more than 90% pure on polyacrylamide gel electrophoresis, and the molecular weight of the enzyme was calculated to be 110 000. The enzyme exhibited absorption maxima at 280, 330 and 370 nm. The 370 nm peak decreased with increase in the 330 nm peak on addition of arginine Km values for arginine, alpha-ketoglutarate, glutamate and alpha-keto-delta-guanidinovalerate were 2.9, 8.1, 25 and 0.30 mM, respectively. Those for pyridoxal 5'-phosphate and pyridoxamine 5'-phosphate were 0.25 and 0.57 microM. The enzyme reacted optimally at pH 8.0--8.5. The synthesis of arginine-alpha-ketoglutarate transaminase was inducible by arginine and alpha-keto-delta-guanidinovalerate.