Lactaldehyde is an intermediate in the methylglyoxal metabolic pathway

Methylglyoxal pathway

The methylglyoxal pathway is an offshoot of glycolysis found in some prokaryotes, which converts glucose into methylglyoxal and then into pyruvate. However unlike glycolysis the methylglyoxal pathway does not produce adenosine triphosphate, ATP...

. Methylglyoxal

Methylglyoxal

Methylglyoxal, also called pyruvaldehyde or 2-oxopropanal is the aldehyde form of pyruvic acid. It has two carbonyl groups, so it is a dicarbonyl compound. Methylglyoxal is both an aldehyde and a ketone....

 is converted to D-lactaldehyde by glycerol dehydrogenase

Glycerol dehydrogenase

In enzymology, a glycerol dehydrogenase is an enzyme that catalyzes the chemical reaction:Thus, the two substrates of this enzyme are glycerol and NAD+, whereas its three products are glycerone, NADH, and H+....

 (gldA). Lactaldehyde is then oxidized to lactic acid

Lactic acid

Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3...

 by aldehyde dehydrogenase

Aldehyde dehydrogenase

Aldehyde dehydrogenases are a group of enzymes that catalyse the oxidation of aldehydes.- Function :Aldehyde dehydrogenase is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids, which leave the liver and are metabolized by the body’s muscle and heart...

.

Lactaldehyde exists in several forms: in open-chain form and as cyclic hemiacetal

Hemiacetal

Hemiacetals and hemiketals are compounds that are derived from aldehydes and ketones respectively. The Greek word hèmi means half...

; in solution and in crystal forms; as monomer

Monomer

A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...

 and as dimer. In crystal form, three conformers occur as hemiacetal dimers with a 1,4-dioxane

1,4-Dioxane

1,4-Dioxane, often called dioxane because the other isomers of dioxane are rare, is a heterocyclic organic compound. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. It is classified as an ether. This colorless liquid is mainly used as a stabilizer for the solvent...

ring skeleton. In equilibrium solution, negligibly small amounts of the monomer and at least one five-membered ring dimer exist.