| Abstract: | A cell-free system for converting tryptophan precursor into violacein pigments is reported. Crucial factors were the requirements of the reduced nicotinamides as a cofactor and Zn2+ as a metal ion. Optimal pHs were in the range of 8.5–9.5. The effectiveness of NADH was thirty times lower than that of NADPH at a low concentration of 2mm. The oxygenation mechanism(s) is discussed by using oxygenase inhibitors such as amethopterin, metyrapone, ancymidol, and prohexadione. Metal-chelating agents strongly inhibited the biosynthesis, suggesting that metallo-enzymes are involved in the biosynthesis. |
