SOME DATA ON THE NATURE OF SULFUR-CONTAINING PEPTIDE-NUCLEOTIDE COMPOUNDS OBTAINED FROM CHLORELLA CELLS AT DIFFERENT DEVELOPMENTAL STAGES IN THEIR LIFE CYCLE

Abstract

(1) The sulfur-containing peptide-nucleotide compound(s), whose existence in the TCA-extract of Chlorella cells has been discovered previously, was separated from synchronously grown algal cells at different stages of their life cycle. As far as the electrophoretic experiments performed at pH 3.6 were concerned, the compound isolated at the stages of cellular ripening (stages of nuclear division) showed almost the same properties as that isolated from younger unripened cells.
(2) When the algal cells were grown in a sulfur-deficient medium, the 1960 Some Data on the Nature of Sulfur-Containing Peptide-Nucleotide 67 TCA-extract prepared by the same procedure contained a nucleotide-complex, which, in the electrophoretic field, behaved almost in the same manner as the normal peptide-nucleotide complex, but, in sharp contrast to the latter, it contained neither sulfur nor the peptide-moiety.
(3) Based on these findings and on the other data thus far obtained, it was inferred that the S-containing peptide-nucleotide complex found in normal cells may be an intermediate in the syntheses of nucleic acids and probably of some proteins, and that the peptide-free nucleotides found in S-starved cells may be a precursor or a remnant moiety of the former, which are incapable of being utilized in the syntheses of nucleic acids owing to the absence of the peptide-moiety.