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Some Amino Acid‐Folic Acid Interrelationships in Tetrahymena pyriformis
Author(s) -
SINGER SAMUEL
Publication year - 1961
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1961.tb01214.x
Subject(s) - methionine , serine , ethionine , tetrahymena pyriformis , biochemistry , folic acid , chemistry , amino acid , reversion , threonine , biology , tetrahymena , phosphorylation , medicine , phenotype , gene
DL‐serine, DL‐methionine or DL‐serine + DL‐methionine in excess inhibited the growth of Tetrahymena pyriformis H. Excess serine was most inhibitory at high concentration of folic acid, whereas the effect of excess methionine or methionine + serine was most pronounced at low levels of folic acid. Inhibition due to excess serine was relieved by raising the level of methionine or by adding pyrimethamine to lower the effective folic acid level, and was intensified by adding Dl.‐ethionine or by raising the level of folic acid. Similarly, inhibition due to excess methionine was relieved by supplying more serine or adding DL‐ethionine (which reduced the amount of available methionine) and was intensified by adding pyrimethamine. Inhibition by excess methionine + serine was reversed by increasing threonine, provided there was ample guanine present. Low levels of guanine or the presence of 8‐azaguanine prevented this reversal. Comparisons are made with the work of others.