A COBALT-PORPHYRIN ENZYME CONVERTS A FATTY ALDEHYDE TO A HYDROCARBON AND CO
A COBALT-PORPHYRIN ENZYME CONVERTS A FATTY ALDEHYDE TO A HYDROCARBON AND CO
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DOI：
10.1073/pnas.89.12.5306
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发表时间：
1992-06-15
影响因子：
11.1
通讯作者：
KOLATTUKUDY, PE
中科院分区：
文献类型：
--
作者：
DENNIS, M;KOLATTUKUDY, PE
烃生物合成的最后一步涉及从脂肪醛中损失CO。这种脱羰基作用是由布朗葡萄球菌的微粒体催化的。在用于溶解脱羰酶的几种洗涤剂中，发现辛基β-葡糖苷（0.1%）是最有效的，并且以可溶形式释放65%的酶活性。用Superose 6对溶解的酶制剂进行FPLC，然后用Mono Q进行离子交换FPLC，导致比活性增加200倍，回收率为7%。纯化的酶每摩尔烃释放近1摩尔CO。酶制剂的SDS/PAGE显示在66和55 kDa处具有相等强度的两条蛋白带。该酶的吸收光谱在410 nm、425 nm、580 nm和620 nm处有谱带，表明存在卟啉。电子探针分析表明该酶含有Co。从B中纯化脱羰基酶。在（CoCl 2）-Co-57中生长的braunii显示Co-57与脱羰基酶共洗脱。这些结果表明，该酶含有钴，可能是钴卟啉的一部分，但不能排除咕啉结构。Co-原卟啉IX本身在60 ℃下引起十八醛的脱羰基，而金属离子或原卟啉单独或几种其他金属卟啉不会引起脱羰基。这些结果强烈表明，烃类的生物合成是由微粒体钴卟啉含酶催化醛的脱羰基，从而揭示了生物功能的Co在植物中的影响。
The final step in hydrocarbon biosynthesis involves loss of CO from a fatty aldehyde. This decarbonylation is catalyzed by microsomes from Botyrococcus braunii. Among the several detergents tested for solubilizing the decarbonylase, octyl beta-glucoside (0.1%) was found to be the most effective and released 65% of the enzyme activity in soluble form. FPLC of the solubilized enzyme preparation with Superose 6 followed by ion-exchange FPLC with Mono Q resulted in 200-fold increase in specific activity with 7% recovery. The purified enzyme released nearly 1 mol of CO for each mol of hydrocarbon. SDS/PAGE of the enzyme preparation showed two protein bands of equal intensity at 66 and 55 kDa. The absorption spectrum of the enzyme with bands at 410 nm, 425 nm, 580 nm, and 620 nm suggests the presence of a porphyrin. Electron microprobe analysis revealed that the enzyme contained Co. Purification of the decarbonylase from B. braunii grown in (CoCl2)-Co-57 showed that Co-57 coeluted with the decarbonylase. These results suggest that the enzyme contains Co that might be part of a Co-porphyrin, although a corrin structure cannot be ruled out. Co-protoporphyrin IX itself caused decarbonylation of octadecanal at 60-degrees-C, whereas the metal ion or protoporphyrin alone, or several other metal porphyrins, did not cause decarbonylation. These results strongly suggest that biosynthesis of hydrocarbons is effected by a microsomal Co-porphyrin-containing enzyme that catalyzes decarbonylation of aldehydes and, thus, reveal a biological function for Co in plants.