Ingvorsen K, Højer-Pedersen B, Godtfredsen S E
Novo Nordisk A/S, Novo Allé, Bagsvaerd, Denmark.
Appl Environ Microbiol. 1991 Jun;57(6):1783-9. doi: 10.1128/aem.57.6.1783-1789.1991.
A cyanide-metabolizing bacterium, strain DF3, isolated from soil was identified as Alcaligenes xylosoxidans subsp. denitrificans. Whole cells and cell extracts of strain DF3 catalyzed hydrolysis of cyanide to formate and ammonia (HCN + 2H2O----HCOOH + NH3) without forming formamide as a free intermediate. The cyanide-hydrolyzing activity was inducibly produced in cells during growth in cyanide-containing media. Cyanate (OCN-) and a wide range of aliphatic and aromatic nitriles were not hydrolyzed by intact cells of A. xylosoxidans subsp. denitrificans DF3. Strain DF3 hydrolyzed cyanide with great efficacy. Thus, by using resting induced cells at a concentration of 11.3 mg (dry weight) per ml, the cyanide concentration could be reduced from 0.97 M (approximately 25,220 ppm) to less than 77 nM (approximately 0.002 ppm) in 55 h. Enzyme purification established that cyanide hydrolysis by A. xylosoxidans subsp. denitrificans DF3 was due to a single intracellular enzyme. The soluble enzyme was purified approximately 160-fold, and the first 25 NH2-terminal amino acids were determined by automated Edman degradation. The molecular mass of the active enzyme (purity, greater than 97% as determined by amino acid sequencing) was estimated to be greater than 300,000 Da. The cyanide-hydrolyzing enzyme of A. xylosoxidans subsp. denitrificans DF3 was tentatively named cyanidase to distinguish it from known nitrilases (EC 3.5.5.1) which act on organic nitriles.
从土壤中分离出的一株氰化物代谢细菌DF3被鉴定为木糖氧化产碱杆菌反硝化亚种。DF3菌株的完整细胞和细胞提取物催化氰化物水解生成甲酸和氨（HCN + 2H₂O→HCOOH + NH₃），且不会形成游离的甲酰胺中间体。在含氰化物培养基中生长期间，细胞可诱导产生氰化物水解活性。木糖氧化产碱杆菌反硝化亚种DF3的完整细胞不会水解氰酸盐（OCN⁻）以及多种脂肪族和芳香族腈类。DF3菌株能高效水解氰化物。因此，使用浓度为每毫升11.3毫克（干重）的静息诱导细胞，在55小时内可将氰化物浓度从0.97 M（约25,220 ppm）降至低于77 nM（约0.002 ppm）。酶纯化结果表明，木糖氧化产碱杆菌反硝化亚种DF3的氰化物水解是由一种细胞内酶引起的。该可溶性酶被纯化了约160倍，并通过自动Edman降解法测定了其前25个氨基末端氨基酸。活性酶的分子量（通过氨基酸测序确定纯度大于97%）估计大于300,000 Da。为了将木糖氧化产碱杆菌反硝化亚种DF3的氰化物水解酶与作用于有机腈类的已知腈水解酶（EC 3.5.5.1）区分开来，暂将其命名为氰化物酶。
