Figure 1.

Yang Cycle Reactions in Bacteria, Yeast, and Plants.

Variations of Yang cycle reactions in bacteria (gene names in lowercase, italic), S. cerevisiae (gene names in parentheses), and plants (enzyme names with MIPS numbers). Plant enzymes identified and characterized in this article (DEP1 and MTI1) are boxed. Closed arrows show reactions found in plants; open arrows show enzymes not found in plants. Met, the end product of the Yang cycle, and MTA, the common byproduct of polyamine, nicotianamine, phytosiderophore, and ethylene biosynthesis, are highlighted. Abbreviations of plant enzymes not mentioned in this article: MAT1 to MAT4, Met adenosyltransferases (=SAM synthases) 1 to 4. Question marks were added to the names of four aminotransferases that might catalyze the conversion of KMTB to Met, as direct proof for this function is still missing.

[See online article for color version of this figure.]