Bull C, Ballou D P
J Biol Chem. 1981 Dec 25;256(24):12673-80.
Protocatechuate dioxygenase has been isolated from Pseudomonas putida. This new species of protocatechuate dioxygenase has been characterized and compared with the enzyme from Pseudomonas aeruginosa. The enzyme reported here has visible absorption, circular dichroism, electron paramagnetic resonance, and Raman spectroscopic properties virtually identical to those for protocatechuate dioxygenase from P. aeruginosa. However, the molecular weight and iron:subunit stoichiometry differ. Protocatechuate dioxygenase from P. putida has a molecular weight of 200,000 and contains 4 alpha subunits of 23,000 daltons, 4 beta subunits of 26,500 daltons, and 4 ferric irons suggesting that the enzyme is a tetramer of (alpha beta Fe+3) catalytic units. Protocatechuate dioxygenase from P. aeruginosa has been reported to have a Mr = 700,000, consisting of 16 alpha subunits of 22,500 daltons, 16 beta subunits of 25,000 daltons, and 8 ferric irons (Yoshida, R., Hori, K., Fujiwara, M., Saeki, Y., Kagamiyama, H., and Nozaki, W. (1976) Biochemistry 15, 4048-4053). This enzyme is thought to be an octamer of (alpha 2 beta 2 Fe+3) catalytic units, although reconstitution with extra iron will somewhat increase its activity. Using stopped flow techniques, we have shown that essentially all of the iron in the P. putida enzyme is catalytically active. This suggests that the minimal catalytic unit of all non-heme iron intradiol dioxygenases is an (alpha beta Fe+3) structure.
原儿茶酸双加氧酶已从恶臭假单胞菌中分离出来。这种新型原儿茶酸双加氧酶已被鉴定，并与铜绿假单胞菌中的该酶进行了比较。本文报道的这种酶的可见吸收光谱、圆二色光谱、电子顺磁共振光谱和拉曼光谱性质与铜绿假单胞菌的原儿茶酸双加氧酶几乎相同。然而，其分子量和铁与亚基的化学计量比有所不同。恶臭假单胞菌的原儿茶酸双加氧酶分子量为200,000，包含4个23,000道尔顿的α亚基、4个26,500道尔顿的β亚基和4个铁离子，这表明该酶是由(αβFe +3)催化单元组成的四聚体。据报道，铜绿假单胞菌的原儿茶酸双加氧酶Mr = 700,000，由16个22,500道尔顿的α亚基、16个25,000道尔顿的β亚基和8个铁离子组成（吉田，R.，堀，K.，藤原，M.，佐伯，Y.，加美山，H.，和野崎，W.（1976年）《生物化学》15，4048 - 4053）。尽管额外添加铁进行重组会在一定程度上提高其活性，但这种酶被认为是由(α2β2Fe +3)催化单元组成的八聚体。使用停流技术，我们已经表明恶臭假单胞菌酶中的几乎所有铁都具有催化活性。这表明所有非血红素铁内二醇双加氧酶的最小催化单元是(αβFe +3)结构。
