L-homocysteine thiolactone

1. arylesterase (homocysteine-thiolactone)

Catalysed by PON1, PON2, PON3cytosol

1. L-homocysteine thiolactone + H2O = L-homocysteine + H(+)

Catalysed by BPHL

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

Catalysed by BPHL, CTH

1. arylesterase (homocysteine-thiolactone)
2. Formation of Homocystine

Catalysed by PON1, PON2, PON3cytosol

1. arylesterase (homocysteine-thiolactone)
2. L-serine hydro-lyase (adding homocysteine
3. N-acetylglutamate synthase (N-acetyl-L-cystathionine)

Catalysed by PON1, PON2, PON3, CBS and 1 morecytosol, mitochondrial matrixOne of 2 routes

1. L-homocysteine thiolactone + H2O = L-homocysteine + H(+)
2. L-homocysteine + H2O = 2-oxobutanoate + hydrogen sulfide + NH4(+) + H(+)
3. 2-hydroxybutyrate:NAD+ oxidoreductase