Sin I L
Biochim Biophys Acta. 1975 Nov 20;410(1):12-20. doi: 10.1016/0005-2744(75)90203-x.
Xanthine dehydrogenase (EC 1.2.1.37) from Pseudomonas acidovorans has been purified to near homogeneity (approx. 65-fold). The enzyme has a molecular weight of about 275 000. Electrophoresis in gels containing sodium dodecyl sulphate showed the presence of two types of subunit with molecular weights of about 81 000 and 63 000. Thus the intact molecule probably contains two of each type of subunit. Xanthine and hypoxanthine are good substrates, and NAD+ is an effective electron acceptor. With xanthine and NAD+ as substrates the purified enzyme has a specific activity of about 20 mumol NADH formed/min per mg protein. Michaelis constants for xanthine and NAD+ are 0.07 and 0.12 mM, respectively, and for hypoxanthine and NAD+ 0.29 and 0.16 mM, respectively.
食酸假单胞菌的黄嘌呤脱氢酶（EC 1.2.1.37）已被纯化至接近均一（约65倍）。该酶的分子量约为275000。在含有十二烷基硫酸钠的凝胶中进行电泳显示存在两种亚基，分子量分别约为81000和63000。因此，完整的分子可能每种亚基各含两个。黄嘌呤和次黄嘌呤是良好的底物，NAD⁺是有效的电子受体。以黄嘌呤和NAD⁺作为底物时，纯化后的酶的比活性约为每毫克蛋白质每分钟形成20 μmol NADH。黄嘌呤和NAD⁺的米氏常数分别为0.07和0.12 mM，次黄嘌呤和NAD⁺的米氏常数分别为0.29和0.16 mM。
