Factors affecting the incorporation of radioactive phosphate into the pentosenucleic acids of brain slices

In the preceding paper (DeLuca, Rossiter & Strick- land, 1953) it was shown that radioactive phosphate (32P) was incorporated into the pentosenucleic acid (PNA) of cat-brain slices respiring in a glucose- containing Krebs-Ringer bicarbonate solution. Factors affecting this incorporation are now de- scribed in more detail. Evidence is presented that the incorporation is dependent upon an active phosphorylating mechanism within the tissue slice.