Ornithine-citrulline enzyme synthesis in biotin-deficient cells of Streptococcus lactis.

In a preliminary report (1) a biotin deficiency in Streptococcus lactis 8039l was found to result, in a greatly diminished ability to convert ornit,hine and carbamyl phosphate to citrulline. In the present investigation a study of the conditions necessary to restore normal activity to biotindeficient, cells has been made. Normal activity is restored to biotindeficient, cells when the cells are incubated for a short time with glucose, phosphate buffer, biotin, and an amino acid supplement which includes glutamine. The requirements for restoration of normal activity and the fact that, this restoration can be inhibited by analogues of purines and pyrimidines or by analogues of amino acids not required in the medium suggest, that synthesis of the enzyme in the presence of biotin is necessary for production of an active enzyme system for the conversion of ornithine to citrulline.