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B6db references: 20012535

type Journal Article
authors Orzechowski, S.; Socha-Hanc, J.; Paszkowski, A.
title Alanine aminotransferase and glycine aminotransferase from maize (Zea mays L.) leaves
journal Acta Biochim Pol
ui 20012535
year (1999)
volume 46
number 2
pages 447-57
keywords Alanine Transaminase/chemistry/isolation & purification/*metabolism
abstract Alanine aminotransferase (AlaAT, EC and glycine aminotransferase (GlyAT, EC, two different enzymes catalyzing transamination reactions with L-alanine as the amino-acid substrate, were examined in maize in which alanine participates substantially in nitrogen transport. Preparative PAGE of a partially purified preparation of aminotransferases from maize leaves gave 6 fractions differing in electrophoretic mobility. The fastest migrating fraction I represents AlaAT specific for L-alanine as amino donor and 2- oxoglutarate as amino acceptor. The remaining fractions showed three aminotransferase activities: L-alanine-2-oxoglutarate, L-alanine- glyoxylate and L-glutamate-glyoxylate. By means of molecular sieving on Zorbax SE-250 two groups of enzymes were distinguished in the PAGE fractions: of about 100 kDa and 50 kDa. Molecular mass of 104 kDa was ascribed to AlaAT in fraction I, while the molecular mass of the three enzymatic activities in 3 fractions of the low electrophoretic mobility was about 50 kDa. The response of these fractions to: aminooxyacetate, 3-chloro-L-alanine and competing amino acids prompted us to suggest that five out of the six preparative PAGE fractions represented GlyAT isoforms, differing from each other by the L-glutamate-glyoxylate:L- alanine-glyoxylate:L-alanine-2-oxoglutarate activity ratio.
last changed 2002/11/12 16:17

B6db references