L-threonine is degrade into methylglyoxal (pyruvaldehyde) by first reacting with a NDA dependent threonine dehydrogenase resulting in the release of a hydrogen ion, an NADH and a 2-amino-3-oxobutanoate. The latter compound reacts spontaneously with a hydrogen ion resulting in the release of a carbon dioxide and a aminoacetone. The aminoacetone in turn reacts with an oxygen and a water molecule through an aminoacetone oxidase resulting in the release of a hydrogen peroxide, ammonium and a methylglyoxal which can then be incorporated in the methylglyoxal degradation pathways.

L-Threonine Degradation to Methylglyoxal References