RESUMEN
Formaldehyde is a compound which is believed to have had a role in evolutionary processes. On the other hand, the (methyl)glyoxalase pathway is a route being present in all biological organisms whereas its function has not yet been recognized in the biochemical machinery. In this article it is raised that (methyl)glyoxalase path might have functioned as a bridge between formose and archaic reductive citric acid cycles in surface metabolists at the early stage of evolution. According to the theory, formaldehyde was essential for the mentioned system as a raw molecule. Based on thermodynamic calculations a simple way of regulation is also shown. The simplicity of the theory may be in a good agreement with and an explanation of why the (methyl)glyoxalase system is of ubiquitous nature.