Bifunctional homocysteine S-methyltransferase/5,10-methylenetetrahydrofolate reductase protein.

Putative cysteine synthase; Belongs to the cysteine synthase/cystathionine beta- synthase family.

Putative O-acetylhomoserine aminocarboxypropyltransferase.

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.

Homocysteine S-methyltransferase.

Putative S-ribosylhomocysteine lyase; Involved in the synthesis of autoinducer 2 (AI-2) which is secreted by bacteria and is used to communicate both the cell density and the metabolic potential of the environment. The regulation of gene expression in response to changes in cell density is called quorum sensing. Catalyzes the transformation of S-ribosylhomocysteine (RHC) to homocysteine (HC) and 4,5-dihydroxy-2,3-pentadione (DPD). Belongs to the LuxS family.

5-methyltetrahydropteroyltriglutamate-- homocysteine S-methyltransferase; Catalyzes the transfer of a methyl group from 5- methyltetrahydrofolate to homocysteine resulting in methionine formation; Belongs to the vitamin-B12 independent methionine synthase family.

Glutathione biosynthesis bifunctional protein gshAB; Synthesizes glutathione from L-glutamate and L-cysteine via gamma-L-glutamyl-L-cysteine; In the N-terminal section; belongs to the glutamate--cysteine ligase type 1 family. Type 2 subfamily.