Comparative Incorporation of S³⁵ L-Cystine and S³⁵ Sodium Sulfate by Normal and Leukemic Leukocytes

1. Certain differences are demonstrated in the metabolic turnover of l-cystine sulfur and inorganic sulfur by normal and leukemic leukocytes. These differences are apparent both in vivo and in vitro and may be associated with factors peculiar to the metabolism of leukemic leukocytes.

2. The incorporation of S³⁵ l-cystine or S³⁵ sodium sulfate by leukocytes appears to be associated primarily with the presence of immature granulocytes.

3. Both l-cystine (or l-cysteine) and sulfate may be of importance in the metabolism of leukocytes.