Aspekte des Thyminstoffwechsels bei Athiorhodaceen

In Rhodopseudomonas spheroides and Rhodospirillum rubrum lack of thymidine kinase activity has been shown to be responsible for the failure of labelling DNA by thymidine or by thymine plus a deoxyribosyl donor, and for the obvious impossibility of selecting thymine auxotrophes by the aminopterin or trimethoprim method. Fluorodeoxyuridine, after in vivo phosphorylation known as inhibitor of the formation of thymidine monophosphate, becomes inhibitory to light‐induced pigment syntheses in Rhodopseudomonas spheroides. This inhibition is overcome by uracil but not by thymidine, indicating that the inhibition by fluorodeoxyuridine is brought about via splitting this compound and incorporation of the fluorouracil moiety into some RNA fractions.