Purification and properties of glutamate dehydrogenase in Scots pine <i>(Pinus sylvestris)</i> needles

Abstract

NADH‐dependent glutamate dehydrogenase (GDH. EC 1. 4. 1.2) was isolated from the needles of Scots pine (Pinus sylverstris L.) grown on a rural and on a heavily polluted industrial area, and it was purified about 500 fold. The purification procedure included salt I'ractionation, ion exchange and affinity chromatography. Miehaelis constants for 2‐oxoglularale (1.7 mM). for ammonium sultate (19 mM ) and for NADH (42.5 resp. 53 μM) the pH optimum (8.5) the requirements for Ca 2+ ions, the temperature dependence ofl the enzyme activity (incubation from 0 to 82°C). and the relation between forest region and electrophoretie isoenzyme pattern were determined. The possible role of GDH in the adaptation of plants to ammonia assimilation (detoxification) under stress conditions, particularly with respect to air pollution, is discussed.