PURIFICATION AND PROPERTIES OF GLUTAMATE-DEHYDROGENASE IN SCOTS PINE (PINUS-SYLVESTRIS) NEEDLES

NADH-dependent glutamate dehydrogenase (GDH, EC 1.4.1.2) was isolated from the needles of Scots pine (Pinus sylvestris L.) grown on a rural and on a heavily polluted industrial area, and it was purified about 5 00 fold. The purification procedure included salt fractionation, ion e xchange and affinity chromatography. Michaelis constants far 2-oxoglut arate (1.7 mM), for ammonium sulfate (19 mM), and for NADH (42.5 resp. 53 mu M), the pH optimum (8.5), the requirements for Ca2+ ions, the t emperature dependence of the enzyme activity (incubation from 0 to 82 degrees C), and the relation between forest region and electrophoretic isoenzyme pattern were determined. The possible role of GDH in the ad aptation of plants to ammonia assimilation (detoxification) under stre ss conditions, particularly with respect to air pollution, is discusse d.