Figure 4.

LC-MS Analysis of GenQ/GenB1-Catalyzed Dehydrogenation and Transamination of G418

Selective ion monitoring was carried out on (A) [M+H]⁺ (m/z 497) and [M+Na]⁺ (m/z 519) ions of G418; (B) the [M+Na]⁺ (m/z 517) ion of 6′-DOG, the product of GenQ-catalyzed 6′-dehydrogenation of G418; (C) [M+H]⁺ (m/z 496) and [M+Na]⁺ (m/z 518) ions of JI-20B, the product of GenB1 catalyzed 6′-amination of 6′-DOG using l-methionine as an amino donor. MS/MS analysis of [M+H]⁺ (m/z 497), [M+Na]⁺ (m/z 517), and [M+H]⁺ (m/z 496) ions is also shown. The peak at m/z 318.1 in Figure 4B arises by further loss of water from fragment m/z 335.93. See also Figures S6 and S7.