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Updated: Mar 18, 2026

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds
Published on: August 8, 2025
Conversion from Tryptophan Precursor into Violacein Pigments by a Cell-free System from Chromobacterium violaceum
1a Department of Applied Biological Chemistry, Faculty of Agriculture , Niigata University , Ikarashi, Niigata 950-21 , Japan.
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 Zn(2+) 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.
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