Figure 3.

Feeding experiments with stable isotope labeled amino acids. Mass spectrum from spent media from Streptomyces sp. NRRL WC-3703 grown on (a) medium alone or medium with (b) D₄-L-tyrosine, (c) D₃,¹³C-methionine, (d) D₁₀-L-leucine, or (e) D₄-L-alanine. (f) Structure of tyrobetaine with likely location of stable isotopes. Yellow bar indicates the m/z for tyrobetaine. Colored bars indicate isotopically labeled tyrobetaine. See Figure S6 for chlorotyrobetaine.