Serine hydroxymethyltransferase; Catalyzes the reversible interconversion of serine and glycine with tetrahydrofolate (THF) serving as the one-carbon carrier. This reaction serves as the major source of one-carbon groups required for the biosynthesis of purines, thymidylate, methionine, and other important biomolecules. Also exhibits THF-independent aldolase activity toward beta-hydroxyamino acids, producing glycine and aldehydes, via a retro-aldol mechanism.

Tryptophan synthase subunit alpha; The alpha subunit is responsible for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate. Belongs to the TrpA family.

Threonine dehydratase; Catalyzes the anaerobic formation of alpha-ketobutyrate and ammonia from threonine in a two-step reaction. The first step involved a dehydration of threonine and a production of enamine intermediates (aminocrotonate), which tautomerizes to its imine form (iminobutyrate). Both intermediates are unstable and short-lived. The second step is the nonenzymatic hydrolysis of the enamine/imine intermediates to form 2- ketobutyrate and free ammonia. In the low water environment of the cell, the second step is accelerated by RidA.

COG1309 Transcriptional regulator.

COG0075 Serine-pyruvate aminotransferase/archaeal aspartate aminotransferase.

COG1045 Serine acetyltransferase.

Glycine cleavage system aminomethyltransferase T; The glycine cleavage system catalyzes the degradation of glycine.

3-phosphoserine/phosphohydroxythreonine aminotransferase; Catalyzes the reversible conversion of 3- phosphohydroxypyruvate to phosphoserine and of 3-hydroxy-2-oxo-4- phosphonooxybutanoate to phosphohydroxythreonine; Belongs to the class-V pyridoxal-phosphate-dependent aminotransferase family. SerC subfamily.

Bifunctional proline dehydrogenase/pyrroline-5-carboxylate dehydrogenase; Oxidizes proline to glutamate for use as a carbon and nitrogen source; In the C-terminal section; belongs to the aldehyde dehydrogenase family.