Lyases;
Carbon-oxygen lyases;
Hydro-lyases
BRITE hierarchy

(R)-2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase [(1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate-forming]

(R)-2-hydroxybutane-1,2,4-tricarboxylate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate (overall reaction) [RN:R09720];
(1a) (R)-2-hydroxybutane-1,2,4-tricarboxylate = (Z)-but-1-ene-1,2,4-tricarboxylate + H2O [RN:R03444];
(1b) (Z)-but-1-ene-1,2,4-tricarboxylate + H2O = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate [RN:R04371]

R03444 R04371 R09720;
(other) R10391 R10392 R10393 R10394 R10395 R10396
Reaction

(R)-2-hydroxybutane-1,2,4-tricarboxylate [CPD:C01251];
(Z)-but-1-ene-1,2,4-tricarboxylate [CPD:C04002];
H2O [CPD:C00001]

This enzyme catalyses several reactions in the pathway of coenzyme-B biosynthesis in methanogenic archaea. Requires a [4Fe-4S] cluster for activity. In contrast to EC 4.2.1.36, homoaconitate hydratase, this enzyme can catalyse both the dehydration of (R)-homocitrate to form cis-homoaconitate and the subsequent hydration reaction that forms homoisocitrate. In addition to cis-homoaconitate, the enzyme can also catalyse the hydration of the physiological substrates dihomoaconitate and trihomoaconitate as well as the non-physiological substrate tetrahomoaconitate. cis-Aconitate and threo-DL-isocitrate cannot act as substrates, and (S)-homocitrate and trans-homoaconitate act as inhibitors of the enzyme.

EC 4.2.1.114 created 2009

1  [PMID:18765671]