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TRANSAMINATION AND THE LIBERATION OF 2‐OXOGLUTARATE BY YEAST
Author(s) -
Lewis M. J.,
Rainbow C.
Publication year - 1963
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1963.tb06349.x
Subject(s) - liberation , ammonia , transamination , thiamine , glutamate receptor , amino acid , yeast , biochemistry , chemistry , methionine , biology , receptor , in vitro
Large amounts of 2‐oxoglutaric acid were liberated by a strain of brewer's yeast during growth on l ‐glutamate as sole major source of nitrogen, the amount being much diminished when ammonia or l ‐asparate was added to supplement l ‐glutamate. During growth on other amino acids, much smaller amounts of 2‐oxoglutarate were liberated; the amount differed according to the particular amino acid supplied and, in general, it was least for those amino acids for which transaminases were demonstrable in cell extracts of the yeast. No detectable quantity was formed during growth on methionine, ammonia or urea. During growth for 48 hr. on l ‐glutamate, oxoglutarate liberated was roughly proportional to glutamate taken up, but in terms of cell dry matter, glutamate uptake and oxoglutarate liberation were greatest in the first 24 hr. Glutamate uptake and oxoglutarate formation were relatively uninfluenced by the presence in the growth medium of added pyridoxin or of pyridoxin and thiamine; however, added alone, thiamine depressed the 48‐hr. growth level, causing a corresponding lowering of oxoglutarate liberation, without affecting glutamate uptake. Pyruvate also accumulated in the medium during growth on l ‐glutamate. Pyruvate formation in terms of unit volume of culture fluid or unit weight of cell dry matter was greatest during growth in the absence of added thiamine.