Open AccessEnzymes involved in ammonia assimilation in the fungus Acremonium persicinum
Author(s) -
Wilcock Melinda J.,
McDougall Barbara M.,
Seviour Robert J.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05441.x
Subject(s) - glutamine synthetase , glutamate dehydrogenase , glutamate synthase , acremonium , ammonium , glutamine , enzyme , transferase , ammonia , biochemistry , substrate (aquarium) , dehydrogenase , chemistry , nitrogen assimilation , biology , glutamate receptor , amino acid , organic chemistry , ecology , receptor , botany
Acremonium persicinum grown in batch culture with ammonium tartrate as the nitrogen source possessed an NADP + ‐dependent glutamate dehydrogenase and a glutamine synthetase. Glutamate synthase was not detected under the culture conditions used. Kinetic studies of the NADP + ‐dependent glutamate dehydrogenase at 25°C and pH 7.6 revealed an apparent K m of 3.2 × 10 −4 M for 2‐oxoglutarate and an apparent K m of 1.0 × 10 −5 M for ammonium ions, with corresponding apparent V max values of 0.089 and 0.13 μmol substrate converted/min/mg of protein, respectively. Glutamine synthetase was measured by the γ‐glutamyl transferase reaction at 30°C and pH 7.55. This transferase reaction of glutamine synthetase had a higher rate at 30°C than at 25°C or 37°C.