L-homocysteine

1. L-homocysteine + H2O = 2-oxobutanoate + hydrogen sulfide + NH4(+) + H(+)

Catalysed by CTH

1. L-homocysteine + ATP = L-homocysteine thiolactone + AMP + diphosphate

Catalysed by MARS1

1. L-homocysteine + ATP + H(+) = L-homocysteinyl-AMP + diphosphate

Catalysed by MARS1

1. L-homocysteine + H2O = 2-oxobutanoate + hydrogen sulfide + NH4(+) + H(+)

Catalysed by CTH

1. (6S)-5-methyl-5,6,7,8-tetrahydrofolate + L-homocysteine = (6S)-5,6,7,8-tetrahydrofolate + L-methionine

Catalysed by MTR

1. (6S)-5-methyl-5,6,7,8-tetrahydrofolate + L-homocysteine = (6S)-5,6,7,8-tetrahydrofolate + L-methionine

Catalysed by MTROne of 3 routes

1. L-homocysteine + L-serine = L,L-cystathionine + H2O

Catalysed by CBS

1. L-homocysteine + glycine betaine = N,N-dimethylglycine + L-methionine

Catalysed by BHMT

1. L-homocysteine + L-serine = L,L-cystathionine + H2O
2. N-acetylglutamate synthase (N-acetyl-L-cystathionine)

Catalysed by CBS, NAGSmitochondrial matrixOne of 2 routes

1. L-homocysteine + H2O = 2-oxobutanoate + hydrogen sulfide + NH4(+) + H(+)
2. 2-hydroxybutyrate:NAD+ oxidoreductase

Catalysed by CTH, LDHB, LDHC, LDHAL6A and 1 morecytosol