Lewis J L, Rhoades C E, Gervasi P G, Griffith W C, Dahl A R
Inhalation Toxicology Research Institute, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico 87185.
Toxicol Appl Pharmacol. 1991 Mar 15;108(1):114-20. doi: 10.1016/0041-008x(91)90274-i.
The cyanide-metabolizing enzyme rhodanese is present in rat nasal epithelium at high activity levels. Cyanide is a common environmental pollutant. It is both toxic and an odorant. The high rhodanese activity in rat nasal epithelium may provide a mechanism for detoxicating inhaled hydrogen cyanide and may also play a role in olfaction by limiting the concentrations of cyanide in the nasal epithelium. The objective of this study was to determine whether high levels of rhodanese activity are also present in human nasal epithelium. On a per milligram mitochondrial protein basis, the rhodanese in human nasal tissue exhibited both a lower affinity (higher Km) for cyanide and a lower maximum velocity (Vmax) for cyanide metabolism than did rhodanese from rat nasal tissue. As in human liver, the human nasal enzyme appeared to exhibit substrate activation by cyanide. Rhodanese activity in the maxilloturbinates of nonsmokers was statistically higher than in smokers although only three samples per group were available. The Vmax/Km ratios for rhodanese from the nasal tissue of nonsmokers were consistently greater, thus suggesting the possibility of higher rates of cyanide metabolism in nonsmokers than in smokers.
氰化物代谢酶硫氰酸酶在大鼠鼻上皮中以高活性水平存在。氰化物是一种常见的环境污染物。它既有毒又有气味。大鼠鼻上皮中硫氰酸酶的高活性可能为吸入的氰化氢解毒提供一种机制，并且还可能通过限制鼻上皮中氰化物的浓度在嗅觉中发挥作用。本研究的目的是确定人鼻上皮中是否也存在高水平的硫氰酸酶活性。以每毫克线粒体蛋白为基础，人鼻组织中的硫氰酸酶与大鼠鼻组织中的硫氰酸酶相比，对氰化物的亲和力较低（较高的Km），氰化物代谢的最大速度（Vmax）也较低。与人肝脏一样，人鼻酶似乎表现出氰化物对底物的激活作用。尽管每组仅有三个样本，但非吸烟者上颌鼻甲中的硫氰酸酶活性在统计学上高于吸烟者。非吸烟者鼻组织中硫氰酸酶的Vmax/Km比值始终更大，因此表明非吸烟者比吸烟者有更高的氰化物代谢率的可能性。
