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Aminotransferase and the Production of Alanine During Hyperosmotic Stress in Paramecium calkinsi
Author(s) -
CRONKITE DONALD L.,
DIEKMAN ALAN B.,
LEWALLEN BETH,
PHILLIPS LISA
Publication year - 1993
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.1993.tb04477.x
Subject(s) - alanine , biology , aminooxyacetic acid , intracellular , osmotic concentration , biochemistry , osmotic shock , osmole , enzyme , amino acid , endocrinology , gene
ABSTRACT When Paramecium calkinsi encounter hyperosmotic stress, intracellular free alanine increases. In vivo assays indicate that the reaction catalyzed by alanine aminotransferase contributes to the build up of alanine in response to hyperosmotic shock. 14 C‐pyruvate is converted to 14 C‐alanine in cells grown axenically at 200 mosm. When shifted to 600 mosm, the rate of conversion of pyruvate to alanine increases, and conversion at either 200 or 600 mosm is blocked by 1 mM aminooxyacetic acid (AOA), an inhibitor of aminotransferase. Intracellular free alanine increase is partially inhibited by AOA, and AOA prevents cells living in fresh water from acclimating to higher salinities, an indication that the increase in intracellular alanine is physiologically significant.