芳香環開裂

概要

芳香族炭化水素の好気的分解は、まず芳香環が水酸化され (upper pathway) 、ジヒドロキシ化合物の芳香環の開裂が起こり、さらに数段階の反応を経て (lower pathway)、最終的にTCA回路の中間体となり経路に組み込まれる。環開裂は、ジオキシゲナーゼによる酸化的開裂で、メタとオルト開裂がある。

環開裂反応

メタ開裂 (meta- [extradiol] cleavage) ：隣接する2つの水酸基の隣で開裂が起こる
オルト開裂 (ortho- [intradiol] cleavage) ：隣接する2つの水酸基の間で開裂が起こる

参考文献

Broderick, J. B. (1999). Catechol dioxygenases. Essays Biochem. 34:173-189. PMID: 10730195
Vaillancourt, F. H. et al. (2006). The ins and outs of ring-cleaving dioxygenases. Crit Rev Biochem Mol Biol. 41(4):241-267. PMID: 16849108

MiFuPへのリンク

オルト開裂経路

NFUNC_0013 Catechol degradation (beta-ketoadipate pathway)
NRULE_0052 Catechol 1,2-dioxygenase
NRULE_0053 (Chloro)muconate cycloisomerase
NRULE_0054 Muconolactone isomerase
NRULE_0070 3-oxoadipate enol-lactonase
NRULE_0071 3-oxoadipate enol-lactone hydrolase/4-carboxymuconolactone decarboxylase
NRULE_0072 3-oxoadipate CoA-transferase subunit A
NRULE_0073 3-oxoadipate CoA-transferase subunit B
NRULE_0074 Beta-ketoadipyl-CoA thiolase
NRULE_0386 Muconate cycloisomerase
NFUNC_0014 Protocatechuate degradation (beta-ketoadipate pathway)
NRULE_0066 Protocatechuate 3,4-dioxygenase alpha subunit
NRULE_0067 Protocatechuate 3,4-dioxygenase beta subunit
NRULE_0068 3-carboxy-cis,cis-muconate cycloisomerase
NRULE_0069 4-carboxymuconolactone decarboxylase
NRULE_0070 3-oxoadipate enol-lactonase
NRULE_0071 3-oxoadipate enol-lactone hydrolase/4-carboxymuconolactone decarboxylase
NRULE_0072 3-oxoadipate CoA-transferase subunit A
NRULE_0073 3-oxoadipate CoA-transferase subunit B
NRULE_0074 Beta-ketoadipyl-CoA thiolase
NFUNC_0104 Chlorocatechol degradation (beta-ketoadipate pathway)
NRULE_0053 (Chloro)muconate cycloisomerase
NRULE_0072 3-oxoadipate CoA-transferase subunit A
NRULE_0073 3-oxoadipate CoA-transferase subunit B
NRULE_0074 Beta-ketoadipyl-CoA thiolase
NRULE_0382 Chlorocatechol 1,2-dioxygenase
NRULE_0383 Dienelactone hydrolase
NRULE_0384 Maleylacetate reductase
NRULE_0385 Chloromuconolactone dehalogenase
NRULE_0387 Chloromuconate cycloisomerase

メタ開裂経路

NFUNC_0011 Dihydroxy aromatic compounds degradation (via meta-cleavage pathway)
NRULE_0058 extradiol dioxygenase
NRULE_0059 meta-cleavage compound hydrolase
NRULE_0060 2-hydroxymuconic semialdehyde dehydrogenase
NRULE_0061 4-oxalocrotonate tautomerase
NRULE_0062 4-oxalocrotonate decarboxylase
NRULE_0063 2-hydroxypent-2,4-dienoate hydratase
NRULE_0064 4-hydroxy-2-oxovalerate aldolase
NRULE_0065 Acetaldehyde dehydrogenase

（更新日 2015-07-22）