Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

5-methyltetrahydropteroyltriglutamate- homocysteine S-methyltransferase; Catalyzes the transfer of a methyl group from 5- methyltetrahydrofolate to homocysteine resulting in methionine formation.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

5,10-methylenetetrahydrofolate reductase; Methylenetetrahydrofolate reductase required to generate the methyl groups necessary for methionine synthetase to convert homocysteine to methionine.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

homocysteine-N5-methyltetrahydrofolate transmethylase, B12-dependent; 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.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

Transcriptional repressor, S-adenosylmethionine-binding; This regulatory protein, when combined with SAM (S- adenosylmethionine) represses the expression of the methionine regulon and of enzymes involved in SAM synthesis. It is also autoregulated.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

S-adenosylmethionine synthetase; Catalyzes the formation of S-adenosylmethionine (AdoMet) from methionine and ATP. The overall synthetic reaction is composed of two sequential steps, AdoMet formation and the subsequent tripolyphosphate hydrolysis which occurs prior to release of AdoMet from the enzyme. Is essential for growth.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

Bifunctional aspartokinase/homoserine dehydrogenase 2; Aspartokinase II and homoserine dehydrogenase II; Protein involved in methionine biosynthetic process and homoserine biosynthetic process.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

Methionine biosynthesis regulon transcriptional regulator; Control of the last step in methionine biosynthesis; MetR is a positive activator of the metA, metE and metH genes. MetR is also a negative regulator of its own expression. Binds homocysteine as an inducer; Belongs to the LysR transcriptional regulatory family.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

Methionine aminotransferase, PLP-dependent; Shows aminotransferase activity with methionine and histidine as substrates, and to a lesser extent also with phenylalanine. Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

Homoserine O-transsuccinylase; Transfers a succinyl group from succinyl-CoA to L-homoserine, forming succinyl-L-homoserine. Utilizes a ping-pong kinetic mechanism in which the succinyl group of succinyl-CoA is initially transferred to the enzyme to form a succinyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O- succinylhomoserine. Cannot use acetyl-CoA. Belongs to the MetA family.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

5-methyltetrahydropteroyltriglutamate- homocysteine S-methyltransferase; Catalyzes the transfer of a methyl group from 5- methyltetrahydrofolate to homocysteine resulting in methionine formation.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

5,10-methylenetetrahydrofolate reductase; Methylenetetrahydrofolate reductase required to generate the methyl groups necessary for methionine synthetase to convert homocysteine to methionine.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

homocysteine-N5-methyltetrahydrofolate transmethylase, B12-dependent; 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.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

Transcriptional repressor, S-adenosylmethionine-binding; This regulatory protein, when combined with SAM (S- adenosylmethionine) represses the expression of the methionine regulon and of enzymes involved in SAM synthesis. It is also autoregulated.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

S-adenosylmethionine synthetase; Catalyzes the formation of S-adenosylmethionine (AdoMet) from methionine and ATP. The overall synthetic reaction is composed of two sequential steps, AdoMet formation and the subsequent tripolyphosphate hydrolysis which occurs prior to release of AdoMet from the enzyme. Is essential for growth.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

Bifunctional aspartokinase/homoserine dehydrogenase 2; Aspartokinase II and homoserine dehydrogenase II; Protein involved in methionine biosynthetic process and homoserine biosynthetic process.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

Methionine biosynthesis regulon transcriptional regulator; Control of the last step in methionine biosynthesis; MetR is a positive activator of the metA, metE and metH genes. MetR is also a negative regulator of its own expression. Binds homocysteine as an inducer; Belongs to the LysR transcriptional regulatory family.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

CP4-6 prophage; Catalyzes methyl transfer from S-methylmethionine or S- adenosylmethionine (less efficient) to homocysteine, selenohomocysteine and less efficiently selenocysteine.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

CP4-6 prophage; Transporter for the intake of S-methylmethionine; Belongs to the amino acid-polyamine-organocation (APC) superfamily. Amino acid transporter (AAT) (TC 2.A.3.1) family.

Cystathionine gamma-synthase, PLP-dependent; Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction. In the absence of thiol, catalyzes gamma-elimination to form 2- oxobutanoate, succinate and ammonia.

Putative oxidoreductase; Catalyzes the NADPH-dependent reduction of 2-oxoglutarate and 2-oxobutanoate, leading to the respective 2-hydroxycarboxylate. Cannot use NADH instead of NADPH as a redox partner. Do not catalyze the reverse reactions; Belongs to the iron-containing alcohol dehydrogenase family.