Methanogen homoaconitase explained

Methanogen homoaconitase
Ec Number:	4.2.1.114

Methanogen homoaconitase (methanogen HACN) is an enzyme with systematic name (R)-2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase ((1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate-forming).^[1] This enzyme catalyses the following chemical reaction

(R)-2-hydroxybutane-1,2,4-tricarboxylate

\rightleftharpoons (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate (overall reaction)

(1a) (R)-2-hydroxybutane-1,2,4-tricarboxylate

\rightleftharpoons (Z)-but-1-ene-1,2,4-tricarboxylate + H₂O

(1b) (Z)-but-1-ene-1,2,4-tricarboxylate + H₂O

\rightleftharpoons (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate

This enzyme catalyses several reactions in the pathway of coenzyme-B biosynthesis in methanogenic archaea.

Notes and References

1. Drevland RM, Jia Y, Palmer DR, Graham DE . Methanogen homoaconitase catalyzes both hydrolyase reactions in coenzyme B biosynthesis . The Journal of Biological Chemistry . 283 . 43 . 28888–96 . October 2008 . 18765671 . 2662002 . 10.1074/jbc.m802159200 . free .