Protein synthesis in vitro with fractions of sea urchin eggs and embryos

Arabinosyl nucleosides. XIII. Influence of arabinofuranosylthymine on DNA-, RNA- and protein-synthesizing systems in vitro

The natural metabolite of the sponge Cryptotethya crypta, arabinofuranosylthymine (araThd), is intracellularly phosphorylated to araTTP. The present study demonstrates that araTTP inhibits both isolated DNA polymerases alpha and the DNA polymerase beta from L5178y cells competitively with respect to the analogous substrate dTTP. The affinity of araTTP is higher to the DNA polymerase alpha than to the DNA polymerase beta. The activity of mammalian DNA-dependent RNA polymerases I, II and III as well as the incorporation rate of a protein cellfree system is not affected by high doses of araTTP.

Protein synthesis of the sponge Geodia cydonium: characterization of the system

The ribosomal population of the sponge Geodia cydonium has been examined. The monosomes have a sedimentation constant of 80 S, the sizes of the subunits are approximately 60 S and 45 S respectively. The polyribosomes contain up to 40 ribosomal units. Cell free protein synthesizing systems (cell homogenate as well as reconstituted system) have been prepared and characterized with respect to Mg(2+), KCI and ATP concentrations, temperature, pH and time course of the reaction. In the cell-free system and in the cellular system the protein biosynthesis is inhibited by chloramphenicol. It is not affected by cycloheximide.