Synthesis of inducible enzymes in irradiated yeast: UV effects on regulation and activity per cell

Abstract

The synthesis of two inducible enzymes in UV irradiated cells was determined during an 8 h postirradiation incubatin. In contrast to the reduction of synthesis shortly after irradiation the effect after a longer period of incubation depends on the radiation sensitivity of the strain. Since exposure inhibits division leading to different cell number in controls and irradiated samples the data are also analysed on a per cell basis. ta considerable increase of the activity per cell was observed. A maximum is reached at the end of the division delay.

Synthesis of Inducible Enzymes in Irradiated Yeast Cells: Inhibition by Ionizing Radiation

“…The arginase assay has been described elsewhere (Gocke and Kiefer 1977) . The cells were always held under repressing conditions before and transferred to inducing medium immediately after exposure at a density of 3 x 10 7 cells/ml except when liquid holding recovery was to be investigated when induction was started after the holding period .…”

“…to the structural gene (Gocke and Kiefer 1978) . It was suggested that radiationinduced division delay is an important parameter in this respect .…”