IRON REDUCTASES FROM PSEUDOMONAS-AERUGINOSA
IRON REDUCTASES FROM PSEUDOMONAS-AERUGINOSA
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DOI：
10.1128/jb.141.1.199-204.1980
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发表时间：
1980-01-01
影响因子：
3.2
通讯作者：
COX, CD
中科院分区：
文献类型：
--
作者：
COX, CD
铜绿假单胞菌的无细胞提取物含有酶活性，当以某些螯合物提供Fe时，所述酶活性将Fe（III）还原为Fe（II），但当Fe未络合时，所述酶活性不还原。铁还原酶活性的2个基板，铁铁螯铁蛋白和柠檬酸铁，似乎是单独的酶，因为在热稳定性的差异，在无细胞提取物的馏分中的位置，在还原剂的特异性和在凝胶过滤色谱过程中的表观尺寸。柠檬酸铁还原酶是在细胞质部分中发现的极不稳定的活性，铁螯铁蛋白铁还原酶是在提取物的周质以及细胞质部分中发现的更稳定的活性。在膜部分中可检测到的少量活性似乎与膜松散相关。虽然这两种酶与NADH的活性最高，还原型谷胱甘肽也与铁螯铁蛋白铁还原酶。O2引起的不可逆损失的百分比的ferripyochelin铁还原酶喷射反应混合物后，而柠檬酸铁的还原酶没有明显的O2的影响。
Cell-free extracts of P. aeruginosa contain enzyme activities which reduce Fe(III) to Fe(II) when Fe is provided in certain chelates, but not when the Fe is uncomplexed. Iron reductase activities for 2 substrates, ferripyochelin and ferric citrate, appear to be separate enzymes because of differences in heat stabilities, in locations in fractions of cell-free extracts, in reductant specificity and in apparent sizes during gel filtration chromatography. Ferric citrate iron reductase is an extremely labile activity found in the cytoplasmic fraction and ferripyochelin iron reductase is a more stable activity found in the periplasmic as well as cytoplasmic fraction of extracts. A small amount of activity detectable in the membrane fraction seemed to be loosely associated with the membranes. Although both enzymes have highest activity with NADH, reduced glutathione also worked with ferripyochelin iron reductase. O2 caused an irreversible loss of a percentage of the ferripyochelin iron reductase following sparge of reaction mixtures, whereas the reductase for ferric citrate was not appreciably affected by O2.