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Observations on enzymes of ammonia assimilation in two different strains ofCyanidium caldarium

✍ Scribed by Carmelo Rigano; Giovanni Aliotta; Vittoria di Martino Rigano


Publisher
Springer
Year
1975
Tongue
English
Weight
298 KB
Volume
104
Category
Article
ISSN
0302-8933

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✦ Synopsis


Two strains of Cyanidium caldarium, one able to utilize nitrate as a substrate, and the other not, were tested for the presence of enzymes of ammonia assimilation. The nitrate-assimilating strain exhibits glutamate dehydrogenase activity. By contrast, the other strain lacks glutamate dehydrogenase; it possesses high alanine dehydrogenase and L-alanine aminotransferase activities which suggest that this strain may incorporate ammonia through reductive amination of pyruvate and may form glutamate from 2-ketoglutarate by a transamination reaction with alanine. Neither strain reveals glutamate synthase activity. Both strains contain similar levels of glutamine synthetase.