Cystathionine beta-lyase (CBL) is found in the Selenoamino acids metabolism pathway and in methionine and cysteine biosynthesis pathways. It converts (seleno)cystathionine to (seleno)homocysteine but is also able to catalyze an alpha, gamma elimination; Uses a pyridoxal phosphate group as cofactor, attached to a lysine residue located in the central section of the enzyme; Localized in the cytoplasm; High confidence in function and specificity.

O-succinylhomoserine sulfhydrylase; Catalyzes the formation of L-homocysteine from O-succinyl-L- homoserine (OSHS) and hydrogen sulfide.

Serine O-acetyltransferase is involved in L-cyteine biosynthesis. It catalyzes the reaction: Acetyl-CoA + L-serine = CoA + O-acetyl-L-serine. Localized in the cytoplasm; High confidence in function and specificity.

Adenosylhomocysteinase; May play a key role in the regulation of the intracellular concentration of adenosylhomocysteine.

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.

Cys/Met metabolism pyridoxal-phosphate-dependent enzymes; Transforms O-acetylhomoserine into L-methionine. Also reacts with other thiols and H2S, producing homocysteine or thioethers; Uses a pyridoxal phosphate group as cofactor, attached to a lysine residue located in the central section of the enzyme; Localized in the cytoplasm; High confidence in function and specificity.

Methionine synthase, homocysteine-binding module; Methionine synthase or 5-methyltetrahydrofolate-homocysteine S-methyltransferase catalyzes the transfer of a methyl group from methyl-cobalamin to homocysteine, yielding enzyme-bound cob(I)alamin and methionine. Subsequently, remethylates the cofactor using methyltetrahydrofolate; L-homocysteine is bound via the zinc atom; Uses the cobalamin (vitamin B12) and zinc as cofactors; This sequence corresponds to the homocysteine-binding domain (Hcy-binding domain) only; Belongs to the vitamin-B12 dependent methionine synthase family; Localize [...]

5-Methyltetrahydropteroyltriglutamate- homocysteine 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.

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.