Quong M W, Miyada C G, Switchenko A C, Goodman T C
Syva Company, Research Department, Palo Alto, CA 94304.
Biochem Biophys Res Commun. 1993 Nov 15;196(3):1323-9. doi: 10.1006/bbrc.1993.2397.
A novel D-arabinitol (DA) dehydrogenase was identified and purified more than 300-fold from Candida tropicalis. The enzyme is specific for DA and catalyzes the NAD(+)-dependent oxidation at carbon 4 to yield D-ribulose. Purification was accomplished by a combination of protamine sulfate and ammonium sulfate precipitation and dye ligand chromatography on a reactive yellow 86 column. The apparent Km of the enzyme for DA ([NAD+] = 2.2 mM) is 39.8 mM. The apparent Km for NAD+ ([DA] = 384 mM) is 0.12 mM. The pH-optimum for the enzymatic oxidation of DA is approximately 10. Cofactor stereospecificity studies demonstrate that the enzyme catalyzes transfer of the 4(S) hydrogen of NADH with D-ribulose as substrate. The polyol substrate specificity of the present DA dehydrogenase makes the enzyme potentially useful for the development of a simple and specific method for the measurement of DA, a metabolite of pathogenic Candida spp. which has been described as a marker for disseminated candidiasis.
一种新型的 D -阿拉伯糖醇（DA）脱氢酶从热带假丝酵母中被鉴定出来，并纯化了 300 多倍。该酶对 DA 具有特异性，催化碳 4 位上依赖 NAD⁺的氧化反应，生成 D -核糖ulose。通过硫酸鱼精蛋白和硫酸铵沉淀以及在活性黄 86 柱上进行染料配体色谱法相结合的方法完成了纯化。该酶对 DA（[NAD⁺]=2.2 mM）的表观 Km 为 39.8 mM。对 NAD⁺（[DA]=384 mM）的表观 Km 为 0.12 mM。DA 的酶促氧化的最适 pH 约为 10。辅因子立体特异性研究表明，以 D -核糖ulose 为底物时，该酶催化 NADH 的 4(S)氢的转移。目前这种 DA 脱氢酶的多元醇底物特异性使得该酶有可能用于开发一种简单且特异的方法来测定 DA，DA 是致病性念珠菌属的一种代谢产物，已被描述为播散性念珠菌病的标志物。
