NEW ARGININE-CONTAINING PEPTIDES ISOLATED FROM CHLORELLA CELLS

Seven kinds of arginine-containing peptides were isolated fromthe cells of Chlorella ellipsoidea, and their structures wereinvestigated. Their amino acid make-ups and quantities presentin randomly grown algal cells were found to be as follows (indecreasing order of contentin moles per dry weight of cells): Arg-Arg, Arg-Arg-Glu, Arg-Arg-Arg, Arg-Glu> Arg-(Arg₂, Glu)-Glu>Arg-(Arg₃,Glu), Arg-(Glu, Asp) Using synchronously mass-cultured algal cells, the quantitiesof these peptides as they changed during the algal life cyclewere followed. It was found that, except in the case of Arg-Arg-Arg,the contents (in moles per dry weight of cells) of the peptides(i) markedly increased during the stages from D_n to L₁, (ii)remained almost constant or more or less appreciably increasedduring the stages from L₁ to L₃, and (iii) decreased sharplyduring the transformation of L₃-cells (via L₄) into D_n-cellsin the dark. The content of Arg-Arg-Arg remained almost constantduring the period from D_n to L₃, and on transference of L₃-cellsin the dark it increased temporarily and then decreased duringthe transformation of L₄-cells into D_n-cells. Significance andpossible roles of these peculiar peptides in the life cycleof Chlorella were discussed. (Received May 10, 1965; )