Serine Synthesis in Tetrahymena from Non-amino Acid Sources; Compounds derived from Serine

SUMMARY: Metabolic products of fermentabie carbohydratesy as well as certain fatty acids, ethanol and acetaldehyde can serve 88 sources for BeFine synthesh in Tekrahpna. Exogenous hydroxypyruvate and related compounds were inactive. Sparing experiments indicate that eerine contributes to the formation of glycine, cysteine (presumably via cytathionine), aminoethmol and thymine. It is becoming increasingly apparent that the serine-glycine interconversion usually represents a source of glycine to the organism rather than a source of serine. One of the most important precursors of serine appears to be carbo