A survey of the presence of glutamate synthase in plant cell suspension cultures

Evidence was sought for the presence of glutamate synthase (EC 2.6.1.53) in extracts from suspension cultures of six higher plant species not previously examined. The level of glutamate synthase measured was above the level of glutamic dehydrogenase (EC 1.4.1.2, 1.4.1.4) in extracts of soybean, parsley, okra, and cotton. Glutamate synthase was detectable but less than glutamic dehydrogenase in extracts of sugarcane. Glutamate synthase was not detected in extracts of peanut. Evidence for two glutamate synthases, each specific for one pyridine nucleotide, was obtained with cultures of carrot. Glutamate synthase has now been detected in eight and possibly nine species representing four and possibly five families of higher plants.