cysteine--tRNA ligase; Belongs to the class-I aminoacyl-tRNA synthetase family.

cysteine--1-D-myo-inosityl 2-amino-2-deoxy-alpha-D-glucopyranoside ligase; Catalyzes the ATP-dependent condensation of GlcN-Ins and L- cysteine to form L-Cys-GlcN-Ins; Belongs to the class-I aminoacyl-tRNA synthetase family. MshC subfamily.

Putative L-serine ammonia-lyase.

Putative glycine 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.

Phosphoserine phosphatase SerB.

Homoserine kinase; Catalyzes the ATP-dependent phosphorylation of L-homoserine to L-homoserine phosphate; Belongs to the GHMP kinase family. Homoserine kinase subfamily.

Homoserine dehydrogenase.

Threonine ammonia-lyase; 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.

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