To test the role of this proposed feedback inhibition in vivo, we created a chimeric enzyme composed of the catalytic domain of the yeast Met13p, and the "regulatory" domain of a plant MTHFR. Even though the plant enzyme possesses a domain homologous to the yeast regulatory domain, the plant enzyme has been shown to be insensitive to inhibition by SAM. What effect will expression of this chimeric enzyme have in yeast?
