PURIFICATION AND SOME PROPERTIES OF ASPARTATE AMINO-TRANSFERASE FROM WHEAT GERM

1. 1. A six-step procedure is described for preparing highly purified aspartate aminotransferase (l-aspartate :2-oxoglutarate aminotransferase, EC 2.6.1.1) from wheat germ. An overall purification of 60-fold was achieved. 2. 2. The purified enzyme was homogeneous, as shown by electrophoresis in starch gel and in polyacrylamide gel. 3. 3. The apparent molecular weight measured by gel filtration was about 75 000. 4. 4. The pH optimum was between 8.0 and 8.5. 5. 5. The holoenzyme was readily resolved, and the apoenzyme was reactivated by pyridoxal 5′-phosphate or pyridoxamine 5′-phosphate. 6. 6. The equilibrium constant was measured for the reaction: l-aspartate + α-oxoglutarate α l-glutamate + Oxaloacetate. 7. 7. There was no evidence for metal-ion activation of this plant aminotransferase. © 1969.