METABOLIC SEGREGATION OF INTRACELLULAR FREE AMINO ACIDS IN PLATYMONAS (CHLOROPHYTA)1

ABSTRACT 14C‐amino acids were supplied to Platymonas subcordiformis (Wille) Hazen and the incorporation of radioactivity into protein and other compounds was followed. Alanine was rapidly metabolized by both N‐limited and N‐sufficient cells. Arginine and lysine were metabolized rapidly by N‐limited cells, but were sequestered from metabolism in N‐sufficient cells. This suggests the existence of two functionally distinct pools; a “metabolic” pool that is rapidly metabolized and preferentially used for incorporation into protein, and a “storage” pool rich in basic amino acids that is sequestered from metabolism.